When I mention "mobile recording" I mean, a vehicle of some sort. When I say "remote" and/or "location" recording, I think of "flypacks" or some sort of portable rig.
If you're considering putting together a mobile unit, you will need (at least) the following 10 key items...
A truck, bus, van or trailer to build your mobile audio control room in.
(Yeah, you could get a plane or boat, but unless you got the bread, you're better off keeping the gear together as a flypack. Then you can set it up anywhere, but that should be another thread all together.)
An isolation transformer so you can float the neutral of your power source.
UPS, voltage regulator and/or power conditioning setup to keep everything nice and clean.
A transformer isolated mic/line splitter with at least two isolated feeds.
A long enough multicore snake for your mics and line inputs to/from the mobile unit.
A communication system so you can talk to your audio assistant on stage.
A video camera and video monitor for closed circuit viewing of your subject.
All the obvious equipment needs ... mics, stands, console, outboard gear, FX processors, multitrack and stereo recorders like RADAR, MX2424, DA98HR, ADAT and/or analog 2" (huh, what's that you say?), et cetera, etc., and your usual DAT, CDR, cassettes, DVDR, VCR, etc. Don't forget, this is a live recording, you will need at least two of everything. Backup is everything when you're on location. And don't forget the HVAC system for a perfect comfort zone.
If you're feeding and receiving your audio to/from other production ventures like the Internet, TV / video / film or broadcast facilities, you will need to transformer isolate all your in/outputs to their setups.
Oh, and a good pair of ears and strong arms to lift all that cable, mics, stands and stuff in and out of each venue you're working in.