Moving From Pattaya To Chiang Mai

I need to hire a truck or large van (weather-proof cargo area) to move two small motorcycles, 150 kg of gear plus three people (driver, myself and girlfriend), a distance of 700 km.

At the end of this month my girlfriend and I will be leaving Pattaya to go live in Chiang Mai. We don't have a lot of stuff to move since we’re moving from one furnished room and into another. We'll be moving two small motorcycles plus 150 kg (300 lbs) of household items.

We have looked at a few trucks for hire here in Pattaya. The most suitable one we've seen so far is basically a modified songthaew (baht bus) without the bench seats and equipped with a higher-than-normal roof. It has canvas sides to deploy in case of rain.

Hitting rain is a real possibility this time of year, especially considering the distance we're traveling. I would feel more confident if the truck had hard sides and roof, like a delivery truck or cargo van. Also, my girlfriend and I will be riding along so a comfortable cab would be a real plus.

Anyone know where I can hire such a vehicle in the Pattaya area?

Thanks!

--RK