Tri-level. Ack. Our last house was tri-level and they're so tricky! Honestly, we ended up moving.

have you thought about turning the lower level into a master suite and adding a family room off the back of the kitchen?

Aesthetically, over the garage is the least desirable. Neighbors who have added a master suite, have done it over the living area, but they did not have the large overhangs your house has. Have you considered getting a four bedroom house instead of trying to add another bedroom? Could you use the lower level? Lot coverage and setbacks are also to be considered.

We also have a split level home, and we just finished a similar project. We toyed with all the ideas you are, and in the end we did as suggested above - made the lower level our master retreat, with two walk in closets, a huge bathroom with laundry closet, and a new bedroom large enough for a king bed and a sitting area. We kept the fireplace that was down there. Not sure what your situation is, but we're empty nesters, and we found ourselves never using the family room that was downstairs before. We LOVE our "retreat"...and we still have three bedrooms upstairs for guests/office. And it was WAY less expensive than any other option.

I see you have some back porch with roof extension. We did big family room with opening to main house and sliding doors to the pool.

May be easier way to convert garage to the room and build new garage?

Have you explored buying another house as Sophie suggests? How about writing to "Love it or List it"? Sounds like you would be an ideal candidate for the makeover.

It might make better sense to look at different home that already has a master suite. The price to move might be cheaper than adding on a master suite. I have a quad level that I love. If I had to use the game room to obtain a master suite I would feel like I was sleeping in the basement even though it is a walkout basement. I wouldn't recommend the bedroom over the garage. Ours is over the garage and even though it is insulated the bath room floor is like ice in the winter.

Of course you need an architect or draftsman before continuing, but why not build out front?

You have not mentioned what the space is like once you step into the front door, so I am guessing living room. What if you made the living room the master and bumped out to the front for the new living room?

I am no architect, but give your ideas to one who will make it work. Something like this:

Nice home.

Shadows make it difficult to tell: Is that a porch behind the front hedge?

Is that the neighbor's house peeking over your roof?

What is your specific objective with this remodel?

Is your objective to add a master bedroom suite in what you expect to be your "forever home"; if so, it makes sense for that suite to be on the ground floor -- unless you actually want to climb stairs in your (likely w/arthritic joints) old age.

If the garage has a concrete floor, building in or over it means dealing with that for plumbing supply and drains unless you build the plumbing to go outside the garage in a new space, however large or small, built beside the garage and/or can access existing supply and drain lines through the adjacent home. And you'll need to add stairs to get there -- and you'll be climbing stairs to get to whatever you put there.

One plus to building over the garage, in addition to keeping the garage, would be that, unlike the home in which you're living, you could empty the garage to remove the existing roof to create the addition.

Without seeing the existing floor plan, suggesting changes isn't practical.

Tri-levels are all very similar and they're very challenging to add on to without looking added on to.

"Love it or list it" is being sued by a couple because of the crappy work they done on their house.