we too, live in an old farmhouse in zone 4 and are putting on a sun porch basically made up of 6 ft Pella sliding french doors with screens and will be surrounded by decking. we were able to purchase the doors (posted on craigslist) used from a apartment building replacing their balcony doors so they were only $200.00 each. we also bought a 10ft sliding french door for the main exit to the deck and main yard. So we will have 2 6 ft sections on each end and the 10fter with a full size window flanking each side, opposite the entrance of the house. we are planning tile floor with a floor drain on the south wall so that we can keep all of our house and tropical patio plants. there is a better homes and gardens magazine : PORCH & SUNROOM PLANNER available at the home centers( got mine at menards for $14.00)that has alot of nice ideas and pictures. There is one sun porch on page 48 that is base on the look of a grain silo and has a metal roof, very country looking and then on page 58 they show a nice way to complete the ceiling with cedar tongue and groove to hide the electric wire and allow the ceiling to be vaulted. hope this helps and I will post finished pics

Thanks for the information! I've been trying to figure out how to get this porch to look the way I imagine it in my head. Pictures will be a huge help.

What a good deal on the Pella french doors. It sounds like your porch is going to be beautiful! That's a great idea to put a drain in the floor for the plants. Hope you post pics when you're finished :)

To help plan our two additions, the new sunroom on one side of the house and a new dining room addition on the other as well as our kitchen remodel I downloaded from IKEA their free kitchen planner program. You can visually see what you want to create. You have a screen to set up the room size, place windows of any size and doors whereever you want. It really helped me to physically see what my mind's eye was imagining

That's a great idea! Thanks for the info :)