Preparation & Stain Recommendations for Refurbished Deck

1. I live in northern Delaware, where we experience four full seasons a year. My deck is fully shaded in the morning, but fully exposed to the sun in the afternoon and evening.

2. The deck is 22 years old, and it was last stained in 2008 with Behr "Plus 10" Solid Oil-Latex Formula stain.

3. A number of rotten boards were just replaced. Both the old and new boards are pressure treated pine. The old boards still have various amounts of the old solid stain on them, and several spots of mildew. But I would like both the new and old boards to match in color as much as possible, while preventing all the boards from deterioration and decay in the future as much as possible.

4. All the old railings and balusters are being replaced with new white maintenance-free railings and balusters.

5. To this end, what do you recommend to best prepare and stain my refurbished deck? When should I prepare and stain the new boards? Should I prepare and stain all the boards at the same time? (If so, should I do it now, in the fall, or wait until the spring?) Lastly, since the deck is about 450 square feet in size, how much of each recommended product should I purchase?

Thank you for your expertise & help!

Rick