Sooo, I put it on the dog, and it fits great! But he looks so embarrassed…I tried to let some other friends in on the coziness, and while it fits them, they look a little bit…ummm…not…happy… Bwaaahahahahahaha!

So many edits to the first one…

Cast on 48 with smaller needles and CC, 2x2 for 12 rounds.
Switch to MC and largest needles and knit, Inc 2 sts every other round to 78 sts.
Place 10 sts on holder for each leg opening, with 14 between legs.
Provisional cast on the leg sts again next round, and knit 27-28 rounds before belly sts.
Work 29 rows with decreases for back. Pick up 3 for 4 along sides, work 12 rounds 2x2.
Legs, 24 sts, 4 rounds MC, 1 round plain CC, 11 rounds 2x2, sewn bind off.

Neck circ. 10”
Chest circ. 15.5”
Back length 14”
Neck to leg 6”
Between armpits 3”

With math:
Neck 10 x 4.5 = 45 (48 for 2x2)
Neck to leg 6
Chest 16+1 x 4.5 = 76.5 (78-80)
Between legs 3 x 4.5 = 13.5 (14)
Around leg 4.5 x 4.5 = 20.5 (24)
Neck to tail 14