Welcome to the forum/community.
Sounds like you had a wonderful initial ride for the LT. The sticking brake isn't normal. I imagine your brake caliper and/or fasteners need some attention. If you don't like the front seat, then try the back seat!
just kidding. I find the stock seat on my '99 to be tolerable, but each rider has their own level of tolerance. If you haven't found out already, there's several aftermarket seat makers mentioned on this site, but most, if not all, are located here in the USA. There's bound to be someone there in Spain or UK, depending on what you're willing to spend. Some riders like an add-on try product called the Airhawk. Maybe you've heard of them.
BTW, that's interesting to hear about m/c not allowed to pull trailers. Is that just in Spain, or a lot of Europe?
Seems like I read of one couple's adventures through Europe, and I'm pretty sure they were pulling a little pop-up camper behind them.
Oh, regarding what to be aware of, since you have an '02 w/ only 20K (miles?), you'll want to read up on the final drives. Also, read up on the weep-hole modification for the slave clutch cylinder? This is preventative medicine. Others talk about replacing the brake lines. And there's another pro-active type modification you might look into, which is for the top case trunk latch assembly. It seems to be a weak design, and everyone swears it's not an "if" but a "when" it breaks. Lots of ideas for farkles/upgrades. One will be regarding the lighting. the LT has crappy headlights, at least before the '05 model.
You're at the right place for all these mods and repairs. This forum will fill you in on more than any other source, including the manufacturer. Just have to use the search feature, which is probably the weakest feature of this site.