Joe,
Important point: If you come here looking for help, please provide as much specific information as you can collect before you even get to the keyboard. You are having heater trouble, and you did have a manufacturer and model, that is good. Collect all the data you can about everything onboard. If you don't have doc for something, that is what websearches are for.
As another that used a MH as a business conveyance, let me start by saying that this can work. One thing to be sure to do is to keep records and receipts for everything. The coach is your place of business and as such all directly related expenses should be deductible. Only line 7 needs to be positive for the business to be legitimate. Line 31 is where you can make the most of it, but do make friends with a bloodthirty tax accountant when you find one. Learn to make Schedule C work for you.
You new coach is actually 8 years old. We are finding that this is about the life of RV tires. Even if the tread looks good, they may be a problem real soon. This is a result of the new materials used to combat HC pollution. It is possible that any other rubber might be an issue. this means fuel, coolant and brake lines. Just keep a close eye on things.
If no one has told you, never leave the dump valves open. You will get to read a lot more about this as time goes by.
If you didn't know it, SD chips seem to have an limited number of clear and re-writes and I don't know what it is.....
I have always carried an inkjet printer/copier/scanner, but you may want better if you are selling prints. This could be a problem because my good printer in the home office is picky about line condition such that I would not even bother trying to run it from the coach generator. I don't have a suggestion for how to deal with that.
I think that I my whole list for the moment.
Matt