Why bother with National Parks?

Sincerely, thanks everyone for the great feedback. I said new to RVing, but we have camped for years. This is a bucket list trip and it's not likely we'll have another opportunity to do this again together. Let me explain some of what I'm finding and my interpretation of it so maybe my postion will be clearer. Roads: As an example we would like to go to see the Sequoia's in Sequoia NP, BUT there doesn't seem to be a road that we can tour with a 27' foot rig (180 and SOME of General's Highway seems to be all that's available to us). Campgrounds: It's NOT that we want (or need) full hookups, but rather it's the fact that you have to make reservations up to a year in advance and we don't want to be tied to a "schedule". Lots of walking: We both are semi-handicapped and have trouble walking long distances. Large crowds: Means long waits and no parking so we may not see/experience anything (we're hoping for) without walking and/or standing in line or maybe even skipping it entirely. So you see, we're not sissy's that want the lap of luxury, but rather a couple of beat up old folks that want to have something special to share together while we can. The anquish that I'm dealing with is because I want to give this trip to my wife(of 43 years) and I'm so afraid it will be a bust.