At 5'4 and 170lb I'm trying to figure the same issue, I sleep all scrunched up anyway but i worry about weight since I'm too short to be able to just step in, and dropside cribs are impossible to get in my country-
I did try one of the toddler bed guards for a while, since I had a daybed enclosed on 3 sides, but it ended up breaking cuz I couldn't screw it into my bed slats (metal bars) so it kept falling sideways or the mattress would slide and push it out of place, and I spent more time fixing it than actually getting to enjoy the infantile effect, so I think it would be easier to just get a crib, but I don't want to spend money on getting a good quality one I've had my eye on for a while, only to find I can't use it-