I don't like rubber hoses in a hot RV doghouse.

I don't like worm drive clamps in an RV doghouse.

Both are a leak waiting to happen.

If you must, then use FI hoses and either FI clamps or constant tension clamps like Oetiker dual ear clamps or Corbin clamps. Corbin clamps are FAA approved on a lot of airplanes. A mechanical fuel pressure gauge can be made pretty safe with braided SS lines, a teenie weenie orifice and/or an isolator. I use a steel braided line for mine. If you have a drill press and a hole saw, isolators are easy to make. Locating the gauge directly above your right knee gives you an early warning system if a leak develops.

But, the main danger of a rubber hose mechanical gauge is leakage in the doghouse, not the cockpit. The heat cycling in the doghouse really age rubber hoses. Especially the heat soak after shutdown.

Another approach (NHRA legal) is to mount the fuel pressure gauge outside the cockpit at the base of the windshield. I did this on several cars that had the rear lip of the hood somewhat open to let hot air out. The gauge was totally out of sight to anyone but the driver.

I just read that Autometer makes fuel pressure isolators for this use.

There is another model that it appears the hiperf diesel truck guys like, http://www.4wheelparts.com/Int...4&t_pt=3524&t_pl=146.

happy motoring!
Matt