I have a 5' long arm frame with, of course, even less width available for quilting. it really doesn't do anything more than a baby quilt. Buuuut, I have quilted many twin and queen sizes on it anyway. If you are only a few inches off, you can certainly make it work. it's not easy, and you have to modify your quilt pattern but it is possible. This really only works for a meander type of quilt pattern or a very custom pattern where you have individual sections or blocks to worry about at a time.
You unfortunately have to baste the layers together in any traditional way, because you will have significant difficulty keeping the wrinkles out of your back and avoiding the layers shifting if you do not baste.
Pin the quilt to your leaders, but don't line up the centers. instead, orient it so that you can quilt from the leftt edge over as far as your machine allows it.
I use quilt clips and treat the whole clip as a "floated" top.
Stitch what you can and rol the quilt like normal. (if using a meandering pattern, be sure to leave a very irregular edge on the right so that you can integrate it better in the end without a visual line).
You will probably only be able to roll the quilt a few times before the quilt starts getting real funky because the right side just is not going to roll properly.
At some point, unpin the top then repin again, but this time orienting it so that you can quilt form the middle (or where you left off) all the way over to the end of the right side.
When you roll as far as you feel comfortable, unpin again and re pin. but this time from the bottom on the quilt in the same 2 ways listed above.
If you are really lucky, then that is all you need to do! but that is unlikely.....
so, then, I unpin everything again and I use more quilt clips to position the quilt onto the back bars (this may not make sense, so I can give pictures if needed) and just keep repositioning as needed to finish all the quilting.
Yes, this is a pain in the butt, but i don't have any choice. if this is kind of sort of is the solution you're looking for, let me know and I can clarify the bits that don't make sense!