For the location, go back to Forest River , they should have it on file, for powering it though it may not be prewired, have your VIN available when you talk with them to confirm.
As to standard or low profile, most 5ers are higher in the front, so unless you want the new unit to be the highest thing on the trailer you will likely need to go low profile. (and it may still be the high point)
Do you have 50 Amp power now? If not you will have to get creative.
If you arent already wired for 50 amp you may want to check out portable units and vent one via hoses through a window or even dryer vent.