I'll try to keep this short! :R My 89 year old mom had spent 50+ years in Hawaii, got dementia, moved back to our old hometown in FL (nobody could tell her no) 3+ years ago. I worked (airlines) in Seattle, lived in Montana, & ended up traveling between the 3 places for over a year, finally had to take early retirement. After a couple of years, Mom started asking "what the heck are we doing in FL?" The rest of the family's in HI for 40+ years, so we moved her (& me) back 8 months ago, now she's asking "what the heck are we doing back here in HI?!" :E
While we're having as much fun as possible on an island, there's only so much you can do. Now that 'the dust is settled', I get to go 'off the rock' every couple of months to do the family business, & when all that's done, I can take about 10 days off for me, every 3 months or so. Every bit of that travel will be RV related! Shows, seminars, driving schools, shopping for my "last RV" and preparing for full time life on the road one day.
So, while we are "creating moments of joy", it's true, people with dementia don't know (mostly) how long you are gone. In fact, my mom still thinks I go to work (on an airplane, in Seattle) or I'd never get a day off! My sister & her hubby are here for help & moral support, & I continue to dream/hope/plan for the day I am once again back on the Mainland & able to get on the open road full time! I think the worst part is not seeing RV's anywhere, there are very few & they are all "very well-traveled". And it's true, you really do get "rock fever"!!! I've lived all over the west, TX, MT, WY, UT, CA, WA, AZ, & it is really hard not being able to see/be in wide open spaces.
To the OP, assisted living is the only way I could do this, even adult day care is a great help, there are a ton of resources at the county/state level to help you find competent elder care, even respite care, so you all can take a break from time to time, & even with limited resources. Do an internet search for elder care, you are not alone! There are also wonderful newsletters that you can sign up for online, you'll get lots of support & help with all kinds of issues & questions.
Best wishes in your journey.