If you are worried about critters install chicken wire barried around foundation about 8" deep. The top edge of the wire should be covered by the floor. I would lay down weed barrier first, no matter what the floor covering. No weeds! If you are worried about too much heat in the summer the best and cheapest bet is to make your poly easily removable. The less poly the more air circulation. Without knowing how your structure is configured I can't tell you if seasonal poly removal will be easy for you or not. It does beat paying fot electricity for fans. The panels can be replaced with framed screens. Pretty easty to make yourself to size.

The box/mantle hoods definitely appeal to me! That's my first choice. I've gotten two quotes from both cabinet places I've been looking at. Midrange cabinetry - first is Wellborn. The second is a local place. Both have quoted about $3500 for EVERYTHING...the hood, blower/insert. I had asked them what a chimney would be vs. a wood hood (all costs). The chimney would be around $1700ish vs. the $3500 for the box hood/blower insert. I think my original cabinet guy worded it wrong when he said a $3k difference. I'm going to a third place Tuesday morning that I went to way way back before we'd started building when I'd had only preliminary ideas. They carry Cardell which is what we had in our last house. I was very happy with those cabinets. I want to see where they come in now that I'm set with how I want things to be. Yes, you're right about the paint. I was thinking that it would show if it was a little off since it was right there next to the cabinets. But I'm sure they could match it closely enough.

Also a cheap alterative to a proper return duct is the use of wall cavities between studs, and also enclosing the space between floor or ceiling joists (i.o.w., unfinished lumber), a BIG no no. Nothing wrong with this... dust settles in plenum return the same way. Now if you were using wall cavities for supply then yes that's a problem because of the resistancebut returns is fine... I would suspect you have some built up construction dust somewhere. Have you checked the furnace filter? That could have built up construction dust. I agree the returns should be vacuumed out, the supply boots maybe but unlikely. Another idea is there is a disconnect in a supply line which is blowing construction dust around.

Here's a fun game to play when it's a small group. Depending on how long you want the game to go on, give each person 5 pennies (or 10 for a longer game). Each person will take a turn saying something about themselves or some experience they had and put one penny into a container (bowl or small jar). The idea is to say something that most likely others in the group might not have experienced because the person that gets rid of all their pennies first wins! (BTW, we had a couple of cheap gifts for whoever won, but you don't have to.) For example, during your turn, if you say something like you were in the military and someone else has been as well that other person gets to put in one penny too. Hope I've explained it clearly. Just know that it's loads of fun and you get to know stuff about others that you never knew before.