I've been doing some more PvP and I'm pretty sure there is no penalty for dying, not even loss of honour points. I fell off a lighthouse which took me down to 450 health, right in front of a red player, they took the entire duration of stun to work out that it was currently a war, and that I really had just landed 10 foot away, like a nice gift wrapped honour package.
He took a little while to actually kill me, I would've gotten away if I had parried his second arrow, which was a dot, instead of the first one, which was a standard shot as I survived the damage, allowing me to stealth, sadly the stealth was broken by the dot. I had my revenge when I respawned though, killed him in a "fair" fight. (I assassinated him, stealthed round a corner, waited for him to turn the building then jumped him)
At any rate - on death, I lost nothing, not even a penny. No honour was lost, no durability (as said by someone else), just pride and, in this case, my footing. Can anyone confirm, because when I killed him, I gained 5 honour points, so I know he must have gained some when he killed me because it was war both times around.
As for leveling - I got about 10 levels through labour use, just simply by having my small farm and a house down, and doing leatherworking. (20K currently). I reached level 50 too, but I prioritised questing because of the equipment (none of us has sufficient weaponry skill as of yet, so our melee weapons are a little weaker than we'd like) and the fact that each time, particularly in the higher level quests, you gain something like 30-40 silver per quest. Quite profitable really.