Do prewash/shrink your flannel first!
I've done many quilts on my sturdy little old vintage machine with the feed dogs engaged, but I could do fancier stuff on borders by making multiple trips around the quilt. You can do a lot with an oval that intersects with a diamond and then a row of outline about an inch away from either side.
Do some searches on "continuous line quilt border" or "pumpkin seed quilt design". Even things like little squares aren't so bad because you sew two sides at a time, turn, do turn, etc. and then go around again. You don't outline each and every square unless you are doing freemotion.