Nan: Car-Rental from Local Shop or International Company?

Hello,

as a holiday-maker, would you rent a small street car out of Nan

• from an international company booked online from company or agency or
• from a local renter?

If from a local renter, what's your experience and cost?

Pondering to rent a *small* street car like Toyota Yaris or smaller out of Nan for about 3-4 weeks (not sure for how long). No off-roading. No pick-up car. Automatic preferred. I wonder if I should

• pre-book Hertz or Avis via Hertz.com or Avis.com
• pre-book Hertz or Avis via internat. agency like rentalcars.com
• shop around local rental stations in Nan (will be in Nan 4 days before car needed)

Here are some prices I found:

• Hertz in Nan via Rentalcars.com: Toyota Yaris or so (small): 940 THB = 26 Euro/day (car small as preferred by me, could even be smaller)
• Hertz in Nan via Hertz.com: Yaris 1200 THB/day (insurance unclear, obv. not best, upgradable locally) (so, more expensive than via agency above)
• Avis in  Nan via Avis.com: "sold out"

--

• Hertz in Nan via Rentalcars.com: Honda City or so (medium): 1100 THB = 30,5 Euro/day  (car larger than preferred)
• Hertz in Nan via Hertz.com: Honda City: 1420 THB/day ((insurance unclear, obv. not best, upgradable locally)

My preferred Europ. agencies (good assistence in damage-cases) do not rent out of Nan, but offer these:

• Avis in Phitsanoluk or Chiang Rai via preferred Europ. agency, good insurance: Toyota Vios or so: 1050 THB = 29 Euro/day  (car larger than preferred)
• Avis oneway-rental Chiang Rai to Phitsanoluk via prefered Europ. agency, good insurance: Toyota Vios or so: 1050 THB = 29 Euro/day  (car larger than preferred)

Would you recommend using a small local renter? (Link to Google Map Search for Nan car-renters) I had local renters already a few times in Nakhon Si Th. and Chiang Mai. Good experience, but I was a more worriless guy back then. I speak basic Thai, but I couldn't say "loose rear mirror" or "broken indicator front left" in Thai.

Pro renting from local dealer

• In my experience, return day is very flexible; return about anytime and pay the exact days of actual use (dislike very unflexible timing with the big companies)
• Can take a look at the car, maybe get "insider information" about vehicle etc.

Contra renting from local dealer

• Don't understand all insurance and procedures
• Not sure about quick emergency assistance on a remote mountain road
• Maybe I have not enough Thai language (it's ok for small talk and tourist things)
• Not sure if cars are availaible when I arrive 4 days before car needed; not totally sure if car will be kept for me as promised
• Some seem to operate through Facebook only, which I loathe (I am usually "hidden" there.)

So what do you think? Thanks!