I solved it by consolidating multiple functions into a 7" Android tablet (used Galaxy tab 4 $85 + $15 64GB SD card):
GPS (Multiple offline map apps loaded, each with various strengths:
HERE,
Maps.ME,
Sygic, Google Maps with some pre-saved areas)
WiFi backup camera OBD code scanner ($10 ELM327 bluetooth +
Torque app)
RV Parky app. (RV CGs, dump stations, etc.)
Gas Buddy (nearby gas w/ prices)
Music library - connected to radio aux. input
Books, Games, Movies for kids when not driving
Internet plan enabled monthly before long trips, with tether enabled for laptop, phones, TV Roku, etc. Or tether to phone plan, depending on data needs.
No TPMS, but there are some smartphone/bluetooth based solutions available. I went with
this cigarette lighter version instead, available for only $70 on eBay.
I'll add a picture of the mount I made for it when I get a chance.
