If you get a Microfridge, check out the models carefully. Some have separate freezer compartments (separate doors for fridge and for freezer), which will keep frozen foods frozen, and some do not. The ones that don't have a separate freezer just have the little "freezer area" for an ice tray. For an office, one without the freezer is probably fine, but for use out here, one will need the freezer. It lets me keep it loaded with frozen stuff like the Jolly Green Giant broccoli and cheese sauce, for example. And it'll keep ice cream frozen (so you don't have to buy it and eat it all right away).
This is the one I have:
http://www.microfridge.com/catalog/product.cgi/1/10/6/P1/default/N/0
It's $469.00 which seems a little pricey, but it's really not. Not for what it does. It gives you a for-real refrigerator that is energy efficient and compact. One large plus, and an absolute requirement for me, is the frost-free freezer. It costs a little more for frost-free, and it uses a little more energy than one that isn't, but, to me, it's a no-brainer. Unless you like defrosting the freezer on a weekly basis, go frost-free. Also, unless you do, in fact, defrost it weekly, then the frost builds up causing the freezer to become grossly inefficient, wasting tons of precious battery amps.
It's got the Safe-Plus, where you plug the fridge/freezer into the microwave, then plug the microwave into the inverter outlet. This controls the unit so that when the microwave is turned on, the fridge/freezer cuts off, and stays off for three minutes after the microwave is finished. This keeps the power consumption lower. It's also important in that you only have the one plug to deal with at the inverter outlet.
It's large enough to easily hold enough groceries for one person for a week or two. You'll want to use a small strip of Velcro to secure the door, otherwise shifting foods inside the fridge will pop it open, sending food all over the place. I just used a 4-inch strip of the "hook" side, then put a couple of 1-inch "fuzzy" sections on the side of the door and the side of the fridge, and use the 4-inch strip as a tab to secure the door. At places like Camping World, you can also get those fridge shelf rods, kind of like a shower curtain rod to place in front of the shelves to keep food from flying off.
The only drawback to the Microfridge is the 700 watt output of the microwave. It's a necessary drawback in order to keep the maximum amp draw to 10 amps AC (110 amps DC), which is important for older building wiring. It draws less amps, but for longer periods of time than a higher wattage microwave. It's got a turntable, so you don't have to microwave foods, turn, then microwave a little more, but because of the lower output, if it says microwave for 6 minutes, plan on doing it for 10 or 12.
So in that respect, the lower wattage microwave actually uses more amps than a more powerful one would. If you have room for a larger, more powerful microwave, and have a 2500 watt or higher inverter, then a better way might be to get the same Microfridge without the attached microwave, and then use them separately. But space in here was also an important factor, and width-wise I didn't want to have the microwave any wider than the fridge.
Incidentally, the HP Photosmart C5180 All-In-One printer/scanner/copier ($179 at Best Buy) fits perfectly on the top of the microwave, secured on the bottom of the printer with four strips of industrial strength Velcro. The paper tray sticks out a couple of inches over the top hanging in front of the microwave, but that's not an issue.
When measuring for space, the width of the unit does not require any extra space in order to fully open the door. On the back of the fridge is that wire rack coolant thing, so you'll need to allow for space behind the unit and the wall for that. I think they say 4 or 6 inches between the rack and the wall. Mine is less than that. There is a drip-tray, at the bottom of the until, in back, where the water collects, then evaporates, from the defrosting cycle. You'll want to be able to get to that every now and then to clean it, to wipe any collected dust off it. Won't need to get to if often, tho, once or twice a year, probably.
The real trick will be securing the Microfridge to the wall. Good luck.