Full cardigan pattern

Keep in mind, that this was totally designed on the fly, and I'm going back and re-constructing what I did, so please forgive me for and alert me to any errors you see! Luckily, many years of experience sewing long before I even picked up my first knitting needles helped me confidently make my set-in sleeves.  They may not be the prettiest buttonholes, but dammit, that's who I figured it out.

Translations:
CO - cast on
K - knit
P - purl
M1 - make one
K2tog - knit 2 together
P2tog - purl 2 together

Equipment: 1 size 6 circular needle (24" long at the very least), 4 size 6 double-pointed needles, some scrap yarn, and a yarn needle for sewing in the loose ends.

Making buttonholes:

• I totally stumbled on this method, so I don't know if it's got a name somewhere, but here is the way I did it
• Knit full length of body for the particular stage in the pattern, until the last 6 stitches
• K1, chain bind off next 3 stitches, leaving 2 remaining
• P2
• This is the tricky bit. Over the years, I've learned to be able to purl backwards (in stockinette, I can keep the right side facing me while doing the purl direction) and here I purl back 2 stitches, then use a chain cast on (only one you can use that I know of here) to cast on 3 new stitches, then I turn around and K1 and complete the row going back.

For body:

• CO 270 stitches (I used a chain cast-on)
• K3 P3 through entire length; next row P3 K3 for full length - total 6 rows of ribbing
• K3 P3 for length until 6 stitches are remaining, K1 to start buttonhole, finish next row as a P3, K3 row
• Do another 6 rows of ribbing
• Row A: P whole length until final 6 stitches - K6
• Row B: K whole length until final 6 stitches - P6
• Repeat Rows A & B 2 more times each
• P full length until final 6 stitches - and make a buttonhole, rest of next row will be like a Row B
• Repeat sets of Rows A & B all the way up the body as long as you like. I made the buttonholes every 2 rows or so (it's not an exact science), and depending on your preferences.
• I started the Intarsia chart when I was 3 inches below the level for the armholes. Feel free to toggle this if you're using a different chart, that's a different height.  Armpit level seemed a good mid-point for the back design.
• I followed the regular Row B for 57 stitches, bound off 20, K2, K2tog knit across the back in the Intarsia pattern (108 stitches), K2tog, K2, then took the 77 stitches for the left arm hole and left front and put them on scrap yarn. The 57 stitches for the right front also went onto scrap yarn at this point.
• Row C: P2, P2tog, work rest in stockinette, including intarsia pattern, for last 4 stitches, P2tog, P2
• Row D: K2, K2tog, work rest in stockinette, @ last 4, K2tog, K2
• Rep Row C and Row D again
• [P whole back, Row D], repeat twice
• Work rest in stockinette, I added another 7 inches after the last decrease, and then bind off.
• Now for the fronts, pick up on the left front (the one still waiting for the underarms to be bound off) and bind off the first 20 stitches from center, K2, K2tog, K to last 6, P6
• Row E: P to last 4 stitches, P2tog, P2
• Row F: K2, K2tog, K to last 6, P6; 
• Repeat Rows E & F twice, and an extra Row E
• [P whole row; repeat Row F] repeat twice
• P whole row; knit whole row; repeat Row E
• K to last 6, P6
• [P whole row; K to last 8, K2tog, P6] repeat until 22 stitches remaining
• [P whole row; K to last 6, P6] repeat for another 2 inches; bind off
• Go back to the other front section, reclaim stitches from the scrap yarn, P row away from arm hole to last 6, K6
• Row G: K to last 4 stitches, K2tog, K2
• Row H: P2, P2tog, P to last 6, K6
• Repeat Row G & Row H again, then an extra Row G
• P to last 6, make buttonhole; on return row, K to last 4, K2tog, K2
• [P to last 6, K6; K to last 4, K2tog, K2] repeat twice
• [P to last 6, K6; K7, K2tog, K to end of row] repeat until 22 stitches remaining, bind off.

Sleeves:

• CO 60 stitches in chain stitch on dpns, join
• K3 P3 around, continue ribbing pattern until cuff is 1 3/4" tall
• K one round
• [K1, M1, K for 5 rows] repeat until sleeve is desired length when tried on your arm, it should go from wrist to your underarm.
• On the left arm, the M1 should be a M1L, and on the right arm, the M1 should be a M1R
• Identify the place where you need to start binding off to shape the sleeve - identify the place 12 stitches before the start, then bind off 12 before the end of the round, and 12 at the start of what would be the next round. If you had dpns and prefer circulars, this is the place to switch over, since it's now essentially being worked flat-ish.
• K2tog, K to last 2 stitches, K2tog
• P2tog, P to last 2 stitches, P2tog
• K2tog, K to last 2 stitches, K2tog
• Purl the whole way
• K2tog, K to last 2 stitches, K2tog
• Purl the whole way
• [K2tog, K to last 2 stitches, K2tog, then work 4 rows in stockinette] - repeat 4 times
• K2tog, K to last 2 stitches, K2tog
• Purl the whole way
• K2tog, K to last 2 stitches, K2tog
• Purl the whole way
• K2tog, K to last 2 stitches, K2tog
• P2tog, P to last 2 stitches, P2tog
• Bind off the rest in a solid bind-off - doesn't have to be super stretchy.

Once the body is done, join the top of back with tops of front (meeting at the shoulders, then sewing toward the collar) and join in the sleeves to their new matching sleeve holes.

Collar:

• Looking at the back of the sweater from the right side (i.e. the intarsia pattern is in view on the right side, not the wrong side), pick up 7 stitches from the (collar) side of the very top of the left front, then pick up each stitch that was bound off across the top of the back, and 7 stitches from the (collar) side of the very top of the left front. This will be the basis of the collar.
• Turn around so that you are staring at the wrong side (and that oh-so-ugly wrong side of the intarsia) and K6, K2tog, knit whole way across top of the back until there are 8 stitches remaining, K2tog, K6
• K5, K2tog, knit until 7 remaining, K2tog, K5
• K4, K2tog, knit until 6 remaining, K2tog, K4
• K3, K2tog, knit until 5 remaining, K2tog, K3
• Bind-off and sew in ends.

Sew in all the loose threads (there will be quite a few from the intarsia, and the different pieces). I found that blocking was also completely essential too. I safety-pinned the front closed while blocking with the garter-stitch panels overlapping to maintain the shape. Then I sewed on the buttons where they lined up with the holes. Mine ended up being quite large and cozy, but I love it. And the pattern on the back was so fantastic that it's been a big hit with my knitting friends. And there's nothing more fun than a frumpy sweater with a fabulous and bad-ass pattern on the back! Business in the front, party in the back!