You may be able to recover your account if you contact support. Anet aren't interested in putting much effort into GW1 these days but account recovery is one area they (apparently) prioritise. If all you're missing is the security question (character name) then all you'll probably need are your CD keys and some personal info.
If that doesn't work out and you're interested in playing (and you don't have other interests competing for that 30 pounds), then buying a new account I think is worthwhile. Do realise though, that the only people that still frequent GW1 fansites are hardcore fans, so yes is probably the only answer you're going to get. As far as activity goes, you generally won't find people looking to do random bits of content. Instead, people tend to be focused on certain things - there are daily missions and such, trading centers (Kamadan), etc, which focus the playerbase. It's recommended to join a guild that suits your needs so that even if there's no one interested in doing what you're doing, there's still a presence. Having said that, GW runs just fine as a single player game. Anet have made changes to ensure that declining activity won't compromise peoples ability to play the game. For example, being able to use seven heroes means that the game is easier and has a much greater capacity for creating builds. In any case, stick to the american districts. Most people are there.