It's only worth it if you have friends already in an active guild / alliance, and you are willing to dedicate a fair amount of time to it.
Else you'll be on your own, and imo, a waste of time and money.
No not really.
This isnt a game where you have to group up with others. 90% of PVE will be based around running around on your own, and naturally coming across other players through the dynamic events system - no need for grouping, you just play and participate with everyone around you.
Group content will be 5 man dungeons, no more than that. The group size was lowered significantly because the main problem in GW1 and other MMOs is how long it takes to form groups with other players. There is no raid type content in GW1 / GW2, just DEs, dungeons and elite areas for the end game, which have the potential to be very hard and challenging, but in GW1 they werent due to how overpowered the meta builds were.
Dynamic Events will eradicate the need for raid type content, and will actually serve a far larger group of players playing together at the same time, but without any delay for having to form groups, or looking for specific healer / tank / DPS roles.
GW1 was very much worth it even when playing solo. Other players quickly became a negative for me compared to playing with AI. There wont be any AI characters in GW2, but the open world is designed to be 100% soloable with difficulty scaling based on the number of players present, and as mentioned above group content is catered for with.
I'll definitely be playing GW2 almost entirely solo from the start. I wont bother with any content that requires grouping, and wont need it (play through the tutorial, then jump straight into WvWvW and DEs).
Also everything that you could possibly need and learn about this game is contained in this one thread:
http://www.guildwars2guru.com/forum/guild-wars-2-mass-info-t25557.html
Its a must read.
I'd love to unlock more hom stuff (i only have something like 8 out of 50 lol) I just don't know where to start or what to do, and even if i did it'd probably be too hard for me to do on my own
Actually its significantly easier and faster to max the HoM, or just get 30 points playing on your own. I've completed Prophecies, Nightfall and Eotn on my second noob account with next to no skill unlocks and playing solo, GW1 has become ridiculously easy today with all the overpowered skill buffs.