I work with similar systems a lot, given the modulation and power output, 1-10km would be a reasonable range band, 10km being line of sight under real world conditions, 1km being light urban propagation. It could theoretically be much worse in a dense urban environment with a high noise floor but I think you can safely put it around or slightly better than the performance of those blister pack FRS walkie talkies.

For comparison, my APRS mobilinkd modem attached to a 5 Watt handheld 144mhz radio will routinely do an order of magnitude better and the same modem on my 50w mobile car radio will approach two orders (double the base range plus additional antenna efficiencies).