When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Not a whole lot. Trucks sit on dealer's lots for longer than that.
Pump tires up to max pressure as indicated on sidewall, maybe change the oil if it has more than 1K miles or so on it and if you want, put a battery maintainer on it or just disconnect the batteries. Also make sure the tank is full and you use some kind of fuel treatment (Stanadyne, etc.) If its going to be outside, a coat of wax would help and if stored in a garage leave a couple of windows cracked a bit.
When you get back, run it a bit at operating temperature and then change the oil and filter.
Keep it out of the rain. And if you have a buddy available, have em go fire it up every now and then. If not, go ahead and disconnect the batteries....pretty much what has already been mentioned above and I think thats all you can do.