A HMO-POS program means that you have to choose a primary care provider. Then if you go to a physician of your choice in another state you will most likely be paying the cost yourself unless your primary care provider authorizes it.
That is very different than having a PPO policy where you can go to anyone throughout the country with no fee or very little, depending on your policy. A PPO policy is highly recommended for full-timers who travel the country. You never need prior authorization from a primary care provider or the insurance comapny. We've never had to pay for services or surgeries as we travel the country.