I was wondering what the fastest way for a P2P member with 50 mining and 41 smithing to level up to the mid 60s in both skills was?

First thing you should do is mine iron ( north of yanny ) and bank it untill you get level 60 mining. Then make some or buy some rings of forging then make iron bars with the iron. then when done smelting go to varrock and make iron naisl fro the construction skill with your iron bars.

I have plenty of nails so far been making for almost 2 hrs have about 2k nails so what should I make with them?