With the handheld CB, you may want to research into more efficient, external antennas. Because they operate on fairly low VHF frequencies, in order to have an efficient (i.e. 'powerful') signal you are best off with an antenna that is a 'quarter wave' - for CB frequencies, that's approximately 2.5 meters long - I suspect the antenna in your vintage CB handheld is substantially shorter! Higher frequency radios - such as the licence free PMR 446, or other radios in the high VHF or UHF bands need much shorter antennas to reach that magic quarter wave length, and thus in a real world, for the same wattage radio, have a much stronger output.
As has been mentioned, a mobile phone remains your best bet (unless you are prepared to invest in the whole emergency beacon or satellite phone route|) in reality, and although that's not as much fun, nor is needing to make an emergency communication!
To get the most out of your new handheld, look into options for external antenna - using wires, ground spikes etc, and i suspect that you could substantially increase its range.