good luck with the trade-in - when I finally sold off half a dozen film cameras a few years back most of them turned out to have mildew inside that made them worthless.
18mm is something like 28mm in old money, which was wide angle then, but you can get wider now. You really only need very wide if you're trying to photograph a building across a narrow street... it'd come in useful for the Jaipur palace, for instance. Zoomier lenses are useful for photographing people from a distance, especially if you don't want them to notice or feel they have to pose. I have a little Lumix for that, just a compact that fits in a pocket but with a big zoom. It's iffy in low light but good in sunny countries.