Look at that as a positive, you only need to do 1/2 of the job

Books first, that way you will understand how everything goes back in place. Since it's mostly exposed, now is the time to check all the wiring and connectors for damage and corrosion too. Look for screw ups by Mr. Alarm installer guy as we as Mr. Stero installer guy and other well meaning but not-to-bright people. GM does not use butt connectors or Scotch Locks. After that get the free cats from Ecklers, Corvette Central, Zips, etc. and start shopping. You only need seat frames as padding and upholstery are both available. Just try to get the car back in driving condition so you can enjoy it. Being able to drive your project will encourage you to finish it rather than letting it sit until you have "time".