Help me evaluate this self storage deal

[James Seely]

Some self storage units in my area have come up for sale and I'm curious on other peoples thoughts on what it's worth.  Sorry in advance, this might be long.

There are 3 storage facilities in this town I will call A, B, and C.  I'm a partner on A.  The owners of B contacted us to see if we wanted to buy.  B has about 60 units and a commercial building under lease for the next 4 years.

2014 numbers

Income - $28900
$9400 - Commercial building
$19500 - Self storage

Expense - $7900
$0 - repairs
$1400 - insurance
$6000 - taxes
$500 - Electric

NOI = $21000
Asking price $320000
CAP Rate = 6.5%

Occupancy
2011 - 90%
2012 - 95%  - this is the year Facility C was built
2013 - 85%
2014 - 75% 

Our facility has run at 98% pretty consistently for many years and didn't see a change when B or C was built.  The properties are all pretty similar except C has room to expand.  I'd grade them all at a B.  Ours may be a little lower as it is the oldest.

Concerns
- some of the units get water in them due to poor drainage
- $0 for repairs the last few years makes me wonder what has been ignored and isn't realistic going forward
- Facility C just got to 85%  I've heard they are going to put up a fence but 85% is also normally where an owner will build more units
- We just received notice that all of the commercial property in our county is going to be reassessed
- A similar property about 10 miles away just sold at a 13 cap.  We purchased ours for 11 cap
- Expenses don't include snow removal and mowing

Upside
- We have had to turn people away for our storage units so this would give us overflow since we can't expand.  Yes I know we should raise prices but these 3 storage facilities are in a town of 1000 people.
- Taking this from 75% occupancy to 95% gets us closer to $35000 NOI
- Current owners say about 25% of their new tenants are looking for our facility but call them because they used the town's name when they named their facility.

Some rough numbers I've come up with for potential offers
$210,000 - assuming a CAP rate similar to our 10%, COC is 23%
$225,000 - Cap rate is 9%ish, COC 18%
$250,000 - Cap rate is 8%ish, COC 14%
$275,000 - Cap rate is 7.5%ish, COC 10%
$300,000 - Cap rate is 7%, COC 7%ish

Personally I don't want to get under 10% COC but there is potential upside that would increase COC if we could get occupancy up.

So what do you think this is worth?

James