You will need help in instances, on RENI you would find a lot of helpful people. But questing is pretty much solo, just need a good weapon and some gear.
just a minor nit Zid; the OP does not "need" to do instances.
To add to my earlier post, there is a great big world out there to explore solo, you can quest, explore, craft, do events, all can be done solo for the most part. Nothing wrong with calling out for help if you find a tough spot to clear, or you can try different strategies etc., go for that lucky crit, yes...
If, however, you are one of those that need to flex their epeen, get to end game right away, etc...well, that would be extremely tough to do solo; not impossible, just tough.