Running the fan continuously could cause a negative air pressure situation in the basement. In intake air has to come from either the windows in the basement or door leading the the first floor. Does the furnace have it's one outside air intake? If not then having the fan run continously is probably not a good idea. Bathroomfanexperts.com has a large array of electronic timers. There is one which can be progammed to go on and off on a 7 day cycle. Perhaps something like that would allow the fan to exhaust the air periodically. I would think the smallest (50CFM?) bathroom fan would be sufficient.

I have laundry in the basement-- have a laundry chute direct to the laundry. I have never wanted a laundry on the second floor but have wished that I had it on the main floor sometimes. Advantage to basement--usually have a lot of room (I don't). We can get really dirty sometimes, with gardening and landscaping projects. Can shuck the dirties in the garage or back entryway and drop down the laundry chute there (or in a bucket in the garage)...vs having to deal with them upstairs (where we have carpet). I wash clothes once a week. Smelly dirty laundry is in the basement; not stinking up the bedrooms. I have a clothesline strung in the unfinished part of the basement for drying rugs, mattress pads, sheets, jeans, etc. during the winter/ rainy days. As well as drip dry items that don't go in the dryer. The clothes line is also handy for hanging wet or damp dirty items to dry (like bath towels & kitchen towels) before they go into the dirty clothes hamper. I fold & sort items as I unload the dryer. Towel stack to the linen closet, DS's clothes in one stack, etc. Usually cart the basket to the main floor and someone else will haul it on upstairs. Have had three laundries that were in enclosed back porches and one just adjacent to the garage when I lived in the south. That arrangement worked really good and would be my preferred location for a laundry. Would not want W/D in a closet if it can be avoided. I use my laundry sink a lot as well as having the washer drain hose empty into the sink. (With a lint sock to keep lint and dog hair out of the sewer line--septic leach field if that's your situation.) You adapt to wherever the laundry is. Pros & cons to wherever it is. Main thing is that a home laundry beats the heck out of having to go to the laundromat! We've probably all had to do that at some time in our lives.

It looks like that long horizontal pipe that goes back toward the water heater is the main drain line for the house? Or is there also a drain in the floor somewhere? Assuming that is your only sewer drain, the water from the washer has to be pumped up higher than that line so that you get it to drain through the P-trap. You have a really short vertical drain standpipe right now on the P-trap, but it works because its a 3" pipe and it is able to clear the water quickly. If you had a standard 2" drain standpipe and it was that short it might fill up and overflow before it drains. If you want to move things around and also put the washer at floor level you may need a special setup to get enough lift for the water. However, remember that many folks spend big money to buy special stands that elevate front loading systems - you have a cheap one already made for you. The lift systems I am talking about are used for basements where the main drain pipe exits part way up the basement wall. They use a large basin to drain the water into, and then a sewage ejector pump to move the water up and into the horizontal drain pipe. Some of these systems can even handle the effluent from a toilet. Bruce

I have a similar sized laundry room. The supply vent is in the floor approximately 2-3 feet from either wall. The problem it is constantly being stepped on and collects debris. Other than that is vent works fine. I suggest installing it away from the traffic flow as much as possible.