Starting to get a build up of weapons, most of which I won't use. What's the best thing to do with them? I tried to mystic forge twice. Not sure if what I got out of it is worth sacrificing 4 weapons but I can't use them yet anyway, level restriction.
The mystic forge is more affectionately known as the "Mystic Toilet" because the chances are usually good that you'll just be flushing money down the drain. It's a cool feature, but unless the recipe is guaranteed (and there are a few) it's not always a great idea. This thread has quite a few "God damn it, I just flushed 100g down the toilet"-type posts, let them serve as a warning. When it works, it's great, but it doesn't always work, so... take that as you will.
If you're just starting out, try using salvage kits (basic will do), as that will give you an influx of crafting materials to use (which is a nice way to level, getting a crafting profession up to 400 = 10 levels).
Later on, when materials aren't quite so important, most people tend to vendor blues and greens they don't want, selling yellows on the TP or breaking them down for Globs of Ectoplasm (a high level crafting material salvaged from level 75+ items). Whites are generally salvaged for crafting material. Sell your yellows first and if you notice any blue or green weapons that are trading higher (Berserker items almost always do, as do certain skins like the Charr "Steam" and Human "Krytan" skins.
I'm on 68 Pinatas. Losing interest fast, but I want/need that achievement for the Shattered Dragon Wings. Consuming candy in tandem and jumping into Dragon Ball matches to change it up a little while Pinatas respawn. I need 10 more wins to be done with them.
You've got until July 9th, so there's no hurry. If you're passing through Lion's Arch, bash a few of them and eventually you'll get there (or at least close enough to quickly finish them off).
I also think there might be a way to get greater volumes of candy coming in the second June update (preview next Tuesday, lands on the 25th). No insider information on this one, just a sneaking suspicion. 100,000 candy seems a little too extreme.