You said you're hesitant about Colorado because of finding 'safe' RV parks.
In our 16 years of full-timing and traveling constantly, we've never stayed in an unsafe place. Use the RV Park Reviews site and you can get an idea. We use public parks 95% of the time - national, state, national forests, COE, county and city parks. We also love to boondock back on gravel roads far from civilization. We've never had an issue to be concerned about.
Don't be afraid of traveling out of your comfort zone. There are fantastic places out there that you need to explore.
I really think trying for a 'different' type of vacation this time will be welcomed by the kids. You have so much vacation time available and it's an awesome country out there. Go for it! :)