If you are worried about doing it, don't. It was easy. Really easy.
Remove all power from the trailer. Then, when swapping the thermostats, only remove one wire at a time from the old thermostat and attach that wire to the same color one on the new thermostat. Then do the next wire.
I did this on two of my previous trailers. You will like the narrower temperature range.
Ben and Doreen
Home Away From Home - 2017 PT Crusader 315RST
TV - 2008 F250 Lariat 4X4 6.4 Diesel
42 nights camping in 2015
57 nights so far in 2016 (a record for us, but Still Not Enough!)