@David S. Here are my thoughts on the properties you are inquiring about and college rentals in general:
Ralland: these are in a less desirable neighborhood and @Dylan Vargas is right, someone would need to come in and purcahse and renovate the entire street for these to hold much value.
Arcadian: this area is just far enough away from campus to get a mix between potential college renters and non-college renters. This property is close enough to Enloe hospital that if well renovated may attract some employees. I am not sure why these 4-plexes have been on the market so long.
Klondike: true, these properties are located close to campus, however, they are located in an area that has become a lower income area with less student renters and more of a lower income clientele. It may be difficult to find a property manager to take on properties in this area.
Regarding college rentals: college rentals can be a very attractive investment. A college rental in the right area generally has very stable demand (unless the college drops enrollment like what happened about 5 years back and the demand went down). College rentals generally command a premium on rent, while I don't think it is a good idea to rent per room (individual leases per room) the students generally look towards the amount of rent per room that they would pay as opposed to the total lease rent. College rentals generally turn over every year, however this offers a few distinct advantages (1) this will happen at the same time every year and it will happen when demand to rent is at its highest, this makes for a cycle that is easy to predict. (2) because turnover happens at the same time you can find out 3-5 months in advance if they are going to be renewing their lease you are able to prepare accordingly by advertising and pre-leasing the property months in advance. You can keep your vacant days to a minimum by pre-scheduling all maintenance and cleaning and advertising for a specific move-in date. (3) you will be able to go into the property each year, make the needed repairs and cleaning and keep it properly kept up to your standards. There are other advantages to college rentals: (1) college rentals in this area are not just leased for the school year and are leased for the entire year (12 month leases) including summer whether they are at the property or not so you are not losing rent during the summer months (2) most students cannot qualify without a cosigner so you have often times multiple cosigners that are guaranteeing the lease.
The downsides to college rentals are that they are generally going to turn over each year so you will have to build some vacancy costs in to your financial models (though you can fairly accurately predict this number because of #2 above). The other downside is that generally college students will be harder on your rentals so wear and tear is higher and items like carpet need to be replaced more often (finding the right long lasting flooring is very important in college rentals).
Good luck in your investment property hunt and let me know if you have any questions about properties, neighborhoods or the market up here in general.