KS, your setup is good to go IMHO. I've hunted unit 15 for the last 12 years with average success. 15 used to be a great unit. But in recent years has become overrun by hunters after it was featured in a couple of magazines. I finally gave up and left to hunt 35 and 36 last year. No regrets. I completely understand why your are looking into another unit. 15 definitely has a good population of elk, but the population of hunters is higher. I'd find another unit too. What the others above have said is all true, but when your talking about unit 15, that may be the exception to their sound advice. Units that I would consider are 421,52,521,14,16,43,45,35,36,42,54,and 78.They all are better than 15 and a decent access to public land. You might want to check out GMUresearch.com for population and other specifics.
Good luck!