I think changing the timing belt of your Esprit is a very good idea. Time is an enemy of timing belts just as miles are. Of course the atmosphere where the car is stored makes a big difference (open air -> car port -> garage -> air conditioned garage). When you replace it, in the future, you will know how old it is and how many miles it's run. Bryan gives some other good things to look at.
Europas are pretty simple. I would think if you're capable of putting one together, you'd be capable of determining if it is road worthy. Start slow. Check everything you can think of (brake bleeding, alignment & ride height, leaks, clutch adjustment, coolant, fan operational, timing, carb tune, tire pressure, engine oil and tranny oil, etc...) and then take it on a short drive to see how it feels. Bring it home and see what's happening. Is something smoking? too hot? not running? clutch out of adjustment? drum brakes out of adjustment? any rattles or noises that shouldn't be there? etc. Fix that and take another short drive and check it again after. You may want the destination of one of those early trips to be a good alignment shop to get a good baseline (especially check the thrust angle of the rear). If you're not confident about your engine tune, maybe a destination might be a classic Brit car shop to have your carbs tuned. If there is no Lotus club in your area (a good bet!), is there an MG, Triumph, or Jag club in your area? They will very likely be very accepting of you and your Europa and someone there might have more experience in some finer points who would be willing to lend his advice.
Good luck and keep us informed!