Thanks for the posts...I'm going to try the wood windowsill if it works out. My cabinet maker/trim guy just told be tonight that I should be there for install of the window trim because it might not be the look I want. The problem is that my cabinets are supposed to meet right up to the window casement, so I don't know if the sill is going to fit right or not?!?! Hope that makes sense, I guess it may be too wide. I hope it can work as I have decided it is the look I'm after!

I'm doing that this week! Please try some of the ideas suggested on the brief Housekeeping included. I have been following their suggestions and am very pleased with the outcome. Last week we replaced a header above one window and will replace one exterior sill and rebuild a window frame for it as well. We used the same dimensions as the original, but replaced all exterior wood with Spanish Cedar. I am priming everything with oil-based primer before reinstalling the parts. It may be to your advantage to hire a carpenter for a day to help with repairs you are not familiar with. If the wood can be stabalized, you may not have to replace it. Try stripping the paint and sanding, carefully, with 60 grit sand paper to see what wood you reveal. We have used a wood hardener on some of our exterior sills with very good one year results. I have found that taking the job on a few windows at a time helps me to retain my sanity. If you have storm windows, you can leave those up while you work on the sash. I then remove the storm during the day while I work on the exterior frame and sill. Make sure you seal the openings at night....I had a bat in my dining room last year! Plan on breaking a few panes of glass while cleaning out the old glazing compound. Good luck and let us know how things are going.

I had to do some temporary fixes with windows that were rotted that looks similar to yours. I just had to wait until I could afford it. I used that wood hardener like you did. To fill in the void after digging out all the rot I used whatever, small pieces of wood. I would put some wood, or something solid under window to keep it supported. I also used some spray foam, use the stuff for windows and doors, it is not supposed to expand so much. I also used some wood putty (not the stuff used for filling nail holes) There is a wood putty that is ready to use, I think made by the same place that makes wood hardener. The other wood putty, it's a powder that you mix with water, Durhams. I then painted/primed to give it more protection...I had 5 windows that looked similar to yours. When we got enough money together to replace we had to replace the bottom framing and a stud or two on a few of them. Yes, I do think the sill/bottom is a support. They are nailed into the side, but the bottom I am sure is "what holds it up." Also, I spray some bleach around the area to kill mold spores, I read somewhere a mixture using borax is good for that too. But after wetting it with the bleach you need to dry it out really good before you seal it all up. The two windows that I had to have studs/bottom 2x4 (that supports the window) replaced I had to tear out drywall and dried it out using fans and portable heaters.

You've made your decision, and congratulations! FWIW, I'll just gently suggest that paint and stain are two very different types of finishes with very different visual effects. It's not often that the two are harmonious together. More often than not, painted walls and painted trim (and cabinets) have a greater chance of harmony, as does stained walls, stained trim (and cabinets). To make painted walls and stained trim harmonious takes a great deal of early design thinking, as well as detailing at the conclusion of design. We see this sort of question frequently on this forum, asking about stained trim, doors, etc. There should be a "sticky" thread for advice!