Hi! Congrats on being a new grad!
I started off at a rehabilitation hospital as a new grad a year and a half ago and am still working there. You really get to see a little bit of everything and you will still have IVPB's, Neb tx's, wound vac's, stumps, trachs, GT's/PEG's/TF's, dialysis patients, PICCs,portacaths I/O caths (especially with spinal cord), halo's, craniotomies/ bone flaps, Burn patients... LOTS!! So yes, I believe it would be a great place for you to learn and start to get a great base for your med/surg skills.
Good thing about rehab (my opinion) is that you can really get to know the patients. Most are there weeks and some months even. I love seeing the progress patients make. Especially alot of the brain injury patients- some will come in coma awakening and leave walking and talking doing great. Amazing.
As for ratios- i think it is the norm for rehab units/hospitals to have higher ratios due to the patients being "more medically stable" Our day ratio (7a-11p) is 1 nurse and tech to 5 or 6 patients. Night is one nurse and tech to 8-9 patients. I work 7p-7a shift and it can get pretty crazy with 9 patients.But i think our hosp. tries to get all the high acuity patients they can. Hopefully with your 11-13 they are not all/most high acuity? That might be something you would want to ask them.
Good luck to you!!!