I'm sure you can find a used one much cheaper on eBay or in TradeAPlane. I'm a pilot so have experience with AS indicators and pitot tubes.
It should should work on a MH, the pitot tube needs unrestriced air flow straight into it. I'd mount the pitot tube anywhere that will give you that. Heaters in them are for when you are flying in clouds, don't think you will be doing much of that. You will need a static vent on the side of the coach for the system to work as that is the "reference pressure". It is called the "pitot-static system". As far as keeping it unclogged,buy a cover for it. Ever notice airplanes on the ramp at the local airport? All will have a red cover with a streamer attached to it on the pitot tube to keep bugs and mud dabbers out. The steamer is to make sure the pilot removes the cover during pre flight as taking off with no AS indicatior is NOT the way to live a long and healthy life.
Wiki has a pretty good write up on the system
Pitot-static system - Wikipedia, the free encyclopedia