Jonathan, I'm a skosh under 5'6" (was a bit over that mark a couple decades ago), and my inseam supposedly is 29". I can flatfoot the bike fine when it's off the stand, but I have been in cross-grade situations (generally in parking lots) where I can get my uphill foot on the ground with no problem, but there's no way with the downhill foot. Not a comfortable feeling. Thus, I've begun a program to lower my bike. (More about that later on another forum.)
I assume that your 1984 has the later-design center stand. Mine doesn't, and the stand on mine is worn/bent to the point that I have trouble getting it off the stand, even on level ground. I'm in the process of installing a 1983-84 design. (See Tech Forum within the next 48 hours for progress report & information request.)
A side stand helps, but not in all cases. Sometimes the center stand is the only safe way. Also, search the R65 archives and the MOA Forum for threads about the downside of parking a hot airhead with a sidestand: oil seeping past the left-cylinder rings & into the combustion chamber, causing the characteristic airhead smoke cloud on restart and a potential long-term problem of carbon buildup on valves piston. Even though it's a PITA, when I dismount and my engine is hot, I try to use the side stand only long enough to permit me to reposition myself to jack the bike onto the center stand. (Bear in mind that Noemi Berry's experience riding R65s for decades doubtless compensates for a lot of her height disadvantage.)
All this does not mean that you should give up hope! By all means, measure the bike off the stand, then have someone measure it with you sitting on it. (It will be lower, obviously, with the shocks under load.) Then try to get the potential buyer to sit on it to see for herself. If she has experience, she should know all this. If she doesn't, then your challenge is to try to build her confidence. IMHO, there isn't a better mid-size bike than the R65 for a small person.
Good luck!
JT