I'm thinking about starting dungeoneering on my tank who is currently f2p. Are there any necessary stats that I need to have before I start? For the most part his skills cover most of what is available on f2p and his range is 80 and def is 99.

Tenacity, stubbornness, perseverance.

Your good to go, although it stinks because range isn't really good in Dungeoneering and you can't mix the vocation armors or it'll lower your range attack bonuses. So, if you don't have crafting levels, it gets a little tough. Don't worry though, you can train crafting there if you need it.