Small Multifamily outdoor space Use What to do?!

[Casey McCoy]

We just acquired a 6 unit building on a half-acre lot, in an awesome location. There is a ton of yard space on this lot and we took the trees down so we'll be relandscaping around the property here and there. The current parking lot has parking spots for 8 cars and the streets are wide here so parking on the street isn't an issue and some tenants currently park on the street already. 

I originally thought about putting a gravel parking area along the front/side of unit D back towards A as there is a curb cut for a drive and 2 units are lower level and the entrance is on that side of the building (cost would be about $5k range for it but would be more of a ). 

I also thought about potentially placing about 8 small storage units to give the tenants a place to rent for an extra fee for their extra stuff.

Do "dog park" areas or private fenced in areas for tenants vs common open yard space see an increase in rents typically? 
There is a large park about 2 blocks away and is in a very walkable neighborhood close to everything in the city (of about 180,000 people) 

Do you have any rules that you have to add in value in this different way? 

My goal is to make the property as attractive as possible for high-quality tenants (as we're doing a full redesign to all the units over the next few months) to stay with as little turn over as possible taking away the majority of their reasons for moving (or as much as we can with a return) 

Any help would be awesome! Thanks in advance! 

Unit location overview