[RWebb]

this is a question in regional economics

the tourist is the flux across the boundary (monetary inflow to the little town)

you write sets of differential equations (some use diffusion models) to characterize the flux and then either try to solve them or just simulate the solutions -- unfortunately sometimes it blows up

that's what some of my economical friends do anyway

It struck me that it was a lot like a heat flow analysis... or a geographically distributed model for biological population dynamics

fill in your own analogy...