One thing that you and others failed to consider is the seasons during which you plan to make your cross country treks from Boise Idaho to upstate NY. It is EXTREMELY challenging to travel by any RV in the northern states from mid-Fall to early Summer. VERY FEW OPEN campgrounds, hazardous driving due to strong winds, flooded and/or icy roads, freezing temps at night - so no RV trips for Thanksgiving, Christmas or Easter visits. :(
How many week long cross country trips do you plan to make during the four summer months - June, July, August, and September? My recommendation is that you consider renting a class-C for your SINGLE summer adventure trip and plan on flying/driving for all other visits. With your 30K budget, consider purchasing a durable, high MPG SUV for your trips that you and DW can easily drive. You'll get to your family faster and have more time to spend with them.