Read through every post on this thread. Have respect for those that have preceeded us. BrianSue, Mexicowanderer, and Pianotuna have always had informative posts.
We have experienced "dirty power" in US and Mexico. Burned out microwaves in Baja and Yucatan. Nearly destroyed an airconditioner at a state park in Colorado. Friends we met in Yucatan and again at Hotel San Ramon (San Miguel) plugged into a post somewhere and it was 220 V. Burned out almost everything.
Our son (who has been in solar for 25 years and is a licensed master electrician) designed and fabricated the solar systems on our 34' fifth wheel and our 19' (2002) Roadtrek.
He designed both systems so that we can either use line power directly or have line power run through battery chargers (1.5 kW for 5th wheel and 1.0 kW for Roadtrek). We tossed the 50 amp cord for the 5th wheel and just keep a heavy duty 15 amp cord in the front bay of 5th wheel where battery suite, PSWI, et reside. We kept the integral 30 amp cord for the Roadtrek. But it goes through the battery charger now (we can change back with a simple switch but choose note to).
This mitigates "dirty power" effects on the electronics but probably does not prevent "hot" skin. We did find clean power at a few places but hot skin elsewhere. We have sufficient solar to run everything during day and fridge on propane at night.
Had thought of grounding the rig and think we may just do this even if the power appears to be clean. Will discuss this with son today since we are mootchdocking at his place of 40 acres in mountains of northern NM (he has put in propane, sewer and water for us).
As noted by a poster above, Hotel San Ramon is a requisite stop for us. Believe we met BrianSue there a few years ago. We stayed at El Pozo RV park in Patzuaro in February this year and it was open and quite nice. Power seemed to be good.
Reed and Elaine