Welcome Andy. The Ultimate Freedom was a fully loaded model for its day.
Tires and batteries are usually the very first things to turn your attention to. And be aware that tires age out before wearing out. Most advise replacing your tires between year 5 - 7 from the DOT date codes on the sidewall. A blowout can be deadly.
Batteries may appear fine but without intimate knowledge of their previous care and use they may not be trustworthy and can lead to many other problems that don’t always seem like battery issues.
You’ve got a Spartan chassis and if you are not very familiar with big diesel chassis I’d get the coach into a full-service Spartan shop and spend the big bucks getting everything checked and made right before using the coach on the road.
All of this will cost many thousands but you’ll be safe and starting from a point of knowledge that everything is taken care of as a baseline for the future. Owning such an RV is an ongoing expense that requires investment far beyond the initial purchase price.
Here’s a link to a 2003 brochure for your RV. If you haven’t seen one it might fill in some blanks.