Basically you do not need a calling card and certainly not expensive roaming charges to be "mobile" in the US. Nearly every shop, every restaurant, public facilities, airports and the hotels as well as holiday homes anyway offer free Wi-Fi. Nevertheless, it can sometimes be very important to be able to make quick phone calls or to be reachable.
A beer on the beach, a small odd job for the improvement of the pocket money, bathing at the top without, the flexible breastfeeding of my toddler or the quickly forgotten parking ticket - that will probably be allowed. Nonsmoking and caution: If you should be taken into police custody because of the suspicion of a crime, is to be expected with a procedure that differs considerably in some respects from that in Germany.
Relax a few days after your trip or a whole vacation in a holiday home. Your neighborhood is mixed: Feel well next to neighbors like the incredibly nice locals, other tourists or even the Snowbirds who are not there in the summer and in the winter months under the sun of the South your soul. There are numerous holiday homes, very well equipped, often with pool and for two, the family or just a whole group.