Cold starting problem

Hey everyone, I'm new here and just picked up my first Previa, last night. My 97 Windstar, blew a headgasket at 189k and I never looked back. I needed something right away, and really liked the look of the Previa. I remember when they first came out and really wanted one, but they were too expensive. I just picked up a 93 LE, for 1800 here in town. It's super clean and a one owner van. A few dings here and there and a crack in the windshield, but no other damage. When I went to pick it up, the owner, couldn't get it started and kept pushing on the gas, which I didn't agree with. At any rate, the van has been sitting for three months without being driven and they told me it never had this problem when it was driven everyday. Today was my first day with it, and it is fairly cold here in Kansas, but she wouldn't start for a few trys and then fired right up. I drove it the rest of the day and it started everytime, right away. Well, it's been sitting for 7 hrs now and I just went out to move it, and it wouldn't start again. After a few trys, it fired right up. Should I drive it for a week and see if that all stops ? Another thing, is that the gas cap was missing and they have been driving it like that for a few years. I put in a bottle of Heat, to remove any water in the tank. Sorry to ramble, I just wanted to get my story out there. Thanx very much. Thom.