As for the *best* places to start - well that will be up to him.
Ive done the leveling at water beetles so i personally prefer to take any char thru the insta TD as i know i get bored looking for mobs.
Alternativly a friend who has done the same hates the TD and prefers looking for mobs.
Take him round hibernia on a tour and he can decide for himself
Friends do help in the game but it really is a personal thing as to what you do in it
And grouping does help but doesnt nescesarily give you the best way of viewing your char
Only solo sometimes has the effect of knowing what your char can/cannot do