If I were you, I'd just go for it. You might end up with a bike that gives you years of enjoyment. But if it doesn't turn out as you hope, you're not doing anything that can't be undone.
How far do you go? As far as you want but, if you haven't done so already, it might be a good idea to just get the bike in a rideable condition and try it out before going very far. The geometry you loved years ago might not be the geometry for you today, especially if you're not quite as flexible as you used to be.