If you want to determine the value why not hire an appraiser? You see we have specialized training. Think of it this way. You have teeth. You brush your teeth and inspect them on a regular basis. You know about your teeth, but that does not make you a dentist.
I don't understand what you mean by "loading" the cap rate. Leases can be net, gross, or modified gross... and you have to verify your rent comps to make adjustments. Once you make proper adjustments to the rent comps, and know a market rent, you can develop a "real" cap rate without playing funny money games.