Good for her thinking of going solo - if she relies on friends, there's a good chance it'll never happen, in my experience! And even if it does, travelling with friends can be difficult for a long period of time if you're not exactly on the same page with where to go/what to do/similar budget - the amount of times I've met people who'd split from friends is crazy. As another poster said, there are certain places (SE Asia, Australia, NZ) that are very popular with 'young' travellers (18-25), and especially people travelling solo....in any of these destinations, you really don't need to use a company for anything, they're so well set up for travellers. I spent most of my gap year in NZ (flew in with no plans, just a visa) and had absolutely no problems, felt safe, made lots of new friends, saw and experienced a lot of new places and things.