Take it to a shop?
You may want to consider taking it over the hill (so to speak..) and having either Andy at Inland RV in Corona, or Ron at C & G Airstream Service in Bellflower take a look at it, and give you their opinions and estimates..
You may well choose to do work yourself, but should at least be able to avoid horrible surprises with a professional evaluation, before you start dropping serious money into restoration...
If the frame or axles or primary electrical are shot, or it has been a mouse-house for a long time, you'll drop $5K before you get very close to the fancy stuff like applainces and interior trim...
In Theory, there's no difference between Theory and Practice, but in Practice, there is usually a difference...