Just seeing the cost of huge storage structures made of steel made me curious. 

Cap rates are also different as being acceptable by an investor of larger multi family as opposed to smaller 5-10 types primarily from effects of early depreciation.As to specialty areas,  I haven't seen Joel's concern as to multi family as much in business and RE, office-warehouse, warehouse, storage facilities, general office are not difficult, I'd rather see an appraiser admit they don't do agriculture, industrial, hotel-motel-hospitality appraisals than attempt to and screw it up costing a few grand.

How does one acurately assess the value of self storage business?

Seeing you're in ND, snow on shoes could cause a major problem with laminate so I wouldn't even consider that.  

If I'm down there and see a property I love, I would probably still buy it, with a regular mortgage.I do have to figure out where I want to live mostly, but some of that will depend on what I can do with the money and how confident I feel about longer term stability.Renting out a Spanish property while I'm in Canada seems somewhat easy, as it's pretty common there to rent out fully furnished places, and tourism rentals would be an option too, to help pay for it.Canada on the other hand, I'd have to put everything in storage or sell it off every time I want to be away and rent the house...

I was in your shoes 1 year ago.

I currently have 5 rental properties that are all single family residences and look forward to expanding my portfolio to contain more income properties like storage sheds, RV parks and commercial properties. 

Is there a good book that describes how to invest in self-storage?

If you were in my shoes would you take the risk?

Looking to learn as much as I can from other people who started in my shoes as well as people who are where I want to be in the future.