Hello Mtracy,
I am also a retired American (non-working).  Although I am currently in the US, I will be moving back to Budva this Spring. In my opinion, Americans are received rather well here (at least in Budva; I can't speak for other coastal communities).  There are quite a few Eastern Europeans (from Russia/Ukraine) that visit/live here as well, and I think our American demeanor is sort of welcomed as a refreshing change.  I have always been treated well and engaged by vendors and in restaurants and shops ... I think many of the locals like the opportunity to practice their English!
Yes, of course it is possible to purchase sea-view property and build on it. It can be very expensive depending on what your requirements are, and how close to civilization and the sea you like to be. The other thing to be aware of is are the restrictions on building a new residence here. Along with restricting what time of year construction is allowed, there are hefty fees for construction permits and other infrastructure-type, community-driven fees.  I have a newer sea view apartment in town, at a 5 minute walk to the beach, with grocery stores, pharmacies, and restaurants all within a one (1) city block walk.  If you don't mind living in town, there are quite a few places with sea views that are available for purchase at prices that are not so terrible and would be quite less expensive than building something from scratch.
I'm afraid I can't advise you on the quality of the healthcare system here. Fortunately, I have not had to use medical services here (yet), but I know they are not up to the level of medical care (or expense) of the US system - and perhaps that is a good thing.  I do know that Montenegro has a socialized medicine system where automatic deductions are taken out of earned income to pay for it, and aside from that one must be able to prove they have minimal medical coverage of some type. I also know one can find most anything needed (in terms of prescriptions) in the pharmacies ... but one might have to hunt around a little to find a pharmacy that can supply you for more uncommon pharmaceuticals (in Budva).Â
I am hoping that the healthier options for food available here and the healthier lifestyle present here will keep me from the having to use medical services here much, if at all.
Best of Luck to You ... perhaps another on this forum can advise about healthcare system.
L.Winsor