just buy the TOGO. "pre-wired" just means there's a 12v source on the roof, run through a switch somewhere. There's no other wiring, just power as it is wifi.
Yes! We found the pre-wiring in the master bedroom. A little black plate. We drilled a hole through the roof as close to the box as we could get. The wiring was just inside that black plate, we had to dig around a little and we just plugged right into that and it worked perfectly.
Our 370fl has a plate near the front over the living room. Had the dealer install prior to delivery and there is a switch in the front cabinet that turns the unit on/off. Works well on LTE and WiFi when the campground WiFi is good.
Note that I am on Verizon and I purchased a SIM card and service for $20 per month unlimited. Actually it is limited to 15GB but far less expensive then Winegard.