Inselhaus is our "home away from home" when we're in Macomb and there's not room with my mother (which, admittedly, isn't often, but I've stayed here several times) down the street. That being said, you won't be staying at my mother's house, so stay at Inselhaus.
The rooms are comfortable, both in appearance and accommodations. The decor brings out Dorothee's island origins but isn't (in the least) kitchee. The beds are comfortable. There's TV (I rarely watch it, so I can't say more than that), a radio that will play your iPod (and maybe or maybe not a CD, I don't recall), and Wi-Fi (for which the is password [**********] in the room, hanging behind the desk lamp if I recall).
Breakfast is always good and varies from day to day, and she can tell you the good places to eat in town (they exist, but apparently nobody can find them), or you can dine in at Inselhaus, but you'll have to ask for the details (remember about my mom; it's not been an issue for me).
The parlor is pleasant without being too formal or too relaxed. The balcony and porch are fine places to sit in good weather, or even almost good weather. The grounds are always beautiful in the summer. The location is ideal (okay, Macomb isn't that large; nonetheless, you couldn't find a better location for access to the Square, University, and more).
In short: Everything is "just so" (yes, I read Kipling as a child). Dorothee won't have it any other way.
And if you want to make a jump start into the B&B business, you could do much worse; make her a good enough offer, and she might be induced to let you take over. Just be sure to keep up the standards she's set.