when i say 4wd i dont mean full on off road 4x4, i mean so that it can better handle rough dirt roads, at a minimum it would need a lockable rear differential and some sort of upgraded suspension, mabey even an air suspension cabin like they use on prime movers would do the job.
2000L works well, half the time you are just using HP lines... which are only about 270LMP max (i think)
As for a monitor, i say spend the $$ on better rescue gear, and just get a pad monitor. are you really going to want to put your truck that close to something requiring a monitor, and remember it is gong to be a PTO pump, so no pump and roll capacity!!,