Since you are going EFI, you'll need a hi-pressure gage.
I did mine EFI in 1995, the gage offerings were nonexistant, so I used (and still use) an
oil pressure sending unit (measures 50 psi just fine) and route the wires to the gage in the dash.
Do not run gas into the passenger compartment.
These days, I bet you can find a real fuel pressure gage for hi-pressure. If it is not electric or isolated, put it outside the passenger compartment.