Someone i was talking to about GW2 said that is EQ2 or whatever the game was that they could level by questing and killing mobs,etc/or doing quests for your trading skills and your profession(?). Like if you are a Leather armor makers you could quest and level that way. If you are a blacksmith you could quest and level that way. Will there be a way to do that in GW2? To level by doing quests for your profession or whatever instead of "go save town...or go kill mobs,etc"
You can gain experience to level up your PvE character by playing through your personal story, by participating in dynamic events, by participating in World vs World vs World pvp battles and/or by simply exploring and killing whatever you run into.
As for your crafting profession... first off, there are no quests in this game, so doing quests for your crafting profession will not be an option. There will be some kind of experience system for crafting (for raising the level of your crafting professions), but from what I understand that will be separate from the experience system for leveling up your character itself. And it wouldn't really be feasible to go from level 1 to 80 by only doing crafting, as you would never unlock any skills - no weapon skills for any of your weapons, no elite skills, and no additional utility skills. In addition, you would never gain any armor or other rewards (though you can probably create all those from crafting as well, if you've got the right combination of crafting professions), and you'd never even unlock any dye colors.
But if you want to do crafting, you will definitely need to collect ingredients. Thus, you will need to explore (and kill the monsters that attack you while you're doing so). That will give you experience, help you unlock skills and equipment, and that will help you get to level 80. So yes, it should be possible to get to level 80 by only exploring and crafting, and if you don't want to, you never have to participate in any dynamic events, you never have to play through the personal story for your character, and you never have to participate in WvWvW battles.