I would suggest you take all those items in small pieces. First, start by finding out the make and model numbers of your fridge and air conditioner. Google those numbers and you will likely find all kinds of good information about trouble shooting and maintenance.
You sound like a pretty handy and determined person, and you will likely just dig in on your own and learn a whole lot more about your rig, and rigs in general by doing it on your own.
A lot of the servicing you talk about it just cleaning vents and tubes, tightening wire terminals, and looking for things that can cause problems, corrosion, dirt and water, bugs and insects and those kinds of things you will just fix yourself and save yourself hundreds of dollars.
If you turn things on, and they work fine, and you have done the above, you are as good to go as about 95% of all rv'ers. If they don't work there is people here that will help.
Bravo to you, and bloooey to your overworking hubby.