folding solar panels

You should get a quality dedicated charger/regulator (eg: ctek d250s) then you wont have any issues with overcharging. There are plenty of other quality chargers but the costs also skyrocket. I ahve the ctek on my ute and its a 12v to 12v charger aswell as a solar regulator in one. Pretty sure you can pick one up for $260 on ebay

Firstly you need to ensure that the panel you are looking at is 12 volts.

I have a fixed 80 watt poly panel on the roof of our van and it works well.
I also have a folding 160 watt set of Mono panels and they work extra well, which I purchased off ebay. Prices have come down considerably in the last 12 months since my buying mine.

Importantly you need a good, 20 amp or better, solar regulator for the set up you are looking for. There is not a huge difference between MPPT or PWM regulators but MPPT is the best.
Monocrystaline panels are reportedly the best but Polycrystaline panels come a very close second.

I have no quams about buying panels from Ebay sellers. I purchased from this bloke panels are good quality and this price seems good as well.

http://www.ebay.com.au/itm/NEW-95W-Solar-Panel-Monocrystalline-Module-12V-/280879688426?pt=AU_Solar&hash=item4165bbeaea

These are well priced also

http://www.ebay.com.au/itm/NEW-145W-Solar-Panel-Monocrystalline-Module-12V-/221043983681?pt=AU_Solar&hash=item33773f8541

As for foldin movable panels and fixed roof mounted panels I can't find a huge difference in my setup. My van batteries are always charged up by about lunchtime and I do not use inverters. Every thing I have runs off 12 volts or I don't have it. Personal preference to cut down on lost energy throught conversion.
I know these are single panels but a couple of hinges and a couple of suitcase clips and you can convert them to folding if you wish or fit them permanently to the van roof. As I say, not a huge difference in outcome from my experience.

Your 240 watts goal seems to be a good choice in my opinion having been in to solar for the last 12 months. I set my folding panels up every day at home as I am running LED lighting in the house and I have had both MPPT regulators on the system as well as PWM regulators.

I am currently leaning toward the 30 watt Fangpusun PWM regulators which have the same circuit as the Steca PWM regulators which have a very easy to interpret display with the battery condition displayed in a fuel guage like format.
see link

http://www.ebay.com.au/itm/20A-Intelligent-Solar-Regulator-LED-Display-12V-24V-FP20A-/261011133915?pt=AU_Solar&hash=item3cc579d5db

I recently bought 2 of these for $90 each from another supplier free postage.
I now have 2 MPPT and 2 PWM regulators and have used all of them so I have some experience with them.

Long winded response but comprehensive I think.

Hope this helps,
Cheers, Bruce.

Sugarcanecampers,
here is a direct link to the Fangpusun regulator I purchased.
Good mob to deal with and good price for that sized unit. As I said i prefer it to the other MPPT units I have.

30 Amp solar regulator