@mazda616 You'll be fine. Jolene is the best Sunbird around and the odds of a mechanical issue that would cancel the trip are very low given how well she's been maintained. Cars NEED to be driven to be reliable.
I usually plan trips based on "miles since last major failure." If the car left me stranded 40 miles ago, then a 50-mile trip is out of the question. At this point, I'm good to drive it to California and back without worrying about it.
If Jolene hasn't left you high and dry somewhere, fill'er up and go!
While past history does not indicate future performance, it's a pretty good indicator. By now you've got a feel for how long she can run. If it's been more than 140 miles since your last breakdown, either you're due for one now, or you'll be fine. I think the exercise will do the old girl some good.