Lars Grimm
Chumono
Fun and exciting Lars! Congrats on the new house and future bonsai garden. All the hard work will be well worth it as you'll be able to appreciate you trees even more so. I would try and go simple with some landscaping, rocks, water features, etc. to accentuate and add interest. Not a lot is needed. After all you want your trees to be the focal point. Definitely lay down weed fabric whether you go with all mulch or gravel or combo like I did. From experience the gravel is easier to keep in terms of weeds but requires clean up and once in a while a good raking to keep it looking its best. Try and design your garden as a whole with visual flow so that it leads the eye from one place to the next.
I regret not having a greenhouse. I used to have one 15 years ago in my old house when I wasn't pursuing bonsai all that seriously. It just figures that now I don't have one when I need it the most. But hopefully I will get one eventually.
I am planning on a second parallel display row that will include some more interesting landscape features. I have access to a place that sells old reclaimed wood from tobacco barns as well as those very large wood beams they use for railroads.
For a Southern version of a water feature, I was thinking of using a half whiskey barrel with a plastic liner and then some carnivorous plants. I found a local plant nursery that propagates everything from seed.