The Ford Alarm is a good quality alarm. All relays are internal, meaning less to go wrong, and easier to install. Yes, if you have some mechanical ability, you should be able to do this yourself, It comes with instructions and a color/location chart for all Ford vehicles.
If you have factory keyless, you need the system 4, if you don't have factory keyless, you need the system 6. You could just wire the camper door into one of the dome light trigger wires. It has a provision for a ground trigger and a positive trigger, and both can be used at the same time to trigger the alarm.
It has a starter kill also. You cut your starter wire in half and hook one end up to a separate wire going to the module and the other to another module wire. It's really easy. I do F trucks in about an hour. Have done them in a half hour, but I was beat.
They want to sell the crappy DEI because they make more money on it. We install Ford alarms for $500, as well as Audiovox alarms for the same price. The audiovox crap, er, uh, unit costs half the price of the Ford unit so we make more money. The Ford unit will also be covered under your original Factory warranty, or if you're out of warranty, 1/12.
So go tell the salesman that a Ford mechanic said he's full of it, and $700 is a huge rip off, and then go to the parts counter for your Ford alarm. If you don't want to do it, an alarm shop will probably be able to install it for you, since it sounds like your dealership likes taking people to the cleaners for alarm installations.
I have one in my truck and love it. They are made by Code Alarm, which is a good alarm company. What I like is that if you tap the truck, the alarm beeps, if you hit it it goes off. Saves on unwanted alarm activations.
Good luck and I hope I was able to help. E-mail me if you need help.
1997 F-150, 4.6, automatic, Dark Toreador Red, Supercab, Flareside, 4X4 Off-Road, Towing Package, Ford hvy dty rubber floor mats, Kenwood 10-disk cd changer, Ford bugshield, Chrome Grizzly Wrap Around Push Bar with 2 KC 100w Daylighters, Ventshades, Ford bedliner, cab and bed professionally undercoated, Code Alarm Sure Start RVS remote starter, Ford alarm, Realistic CB with Wilson Little Wil antenna and Astatic power mic, ported MAF sensor, and Lots of TLC!! (Besides being an F-150 nut, I am a Ford auto technician.)