What makes the difference on whether or not you can continue your trip, or if you break the bank, is IF, and this is the big IF, you can do most of the work/repair/maintenance on your coach.
The above postings are informative but IF you do not have the skills or tools to make those "simple" repairs, what will they do for your trip and what will it cost YOU to pay someone else to fix things?
As mentioned, Class A coaches can be expensive, and can be prohibitively expensive if you have to rely exclusively on paying others to diagnose and repair the issues that come up as you travel around the USA.