You basically have to weigh "can you picture 2-3 more healthy years from him?" vs. "can you imagine RT (and the whole right side of the OL) w/o him?".
Not with who is currently on the roster. Yes, you could shift guys like Block It man or Turner around but I'm not convinced about the depth behind them. Plus, I don't know how well Turner would fare at RT.
If his demands are reasonable for a solid RT I'd sign him. I'd just make sure the contract protects the Packers in case of injury. They still need to draft more depth on Oline even with Buluga onboard.