The best/easiest location to add the surge guard is where your Shore-power cable enters the TT. This will put it between the shore power cable and your AC breaker box.
Mine enters at the rear storage compartment, which made installation easy. Click on my SOLAR album below to see a picture of where I wired in my whole house surge protector in the storage compartment (last picture on right). The way I wired it, it works with the shore-power and with my inverter.
I have always used a whole house model in our TT's (and houses) with no problems. As for monitoring voltage levels, I have AC, DC and SOLAR Panel meters inside the TT.
One little hint, I always hook my TT up to the CC 50Amp service outlet when available, as these receptacles are very seldom used and are in much better shape than the abused 30Amp outlets. If you wiggle the cable on some to the 30 Amp outlets the voltage fluctuates, not very good for the TT's electronics, and may cause some power-guards to trip.
This surge protector setup works for me, but may not be an option for others.
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Our Solar Album http://www.jaycoowners.com/album.php?albumid=329