2001 Pontiac Aztec. What can this car REALLY handle? At 100k, what kind of...

[ddj7x7]

...maintenance does it need? I bought this car new in 2001 thinking I was gonna go camping all the time. Well it's 2008 and I'm finally taking it into the wilderness. I'm going on a hike which first requires a 6 mile drive on rough terrain. It is a 2 wheel drive. Also it just hit 100K miles. The manual says it needs a 100k mile service. Others say "if it works don't fix it...you could make it worse." Preventative maintenance is best....isn't it? What is the very least I should do? What is the best I could do? I want to take good care of my car but I don't really want to go overboard. I want to avoid using my credit card. Tryin' to keep in a budget. Thanks in advance for all of your advice.

[Pedro S]

a proper 100K tune is 400 to 500 dollars....you want cheap? change auto tranny fluid..oil and filter ..new coolant..plugs if youve never done them...