Thats not a bad spot for a filter actually. I run a remote filter under the bed and Id like to move the thing. The OEM filter is a rated for 60GPH I think? maybe get a water sep only or a water-absorbing type on the vacuum side. You can put some spin on filters on the pressure side. The
CAT filters are probably ok. Placing a too restrictive filter on the vacuum side can cause cavitation.
Most of these things seem to come with 3/8 and 1/2 NPT threads. Just get some pushlok fittings and some quality fuel hose. The marine grade hose has a plastic liner which can be really really hard to get on the fitting, BTW.