I'm super fussy who I see (because you dont have a second rent you also don't need to see as many anyway) and its far from an exact science, but I avoid young sounding men (the average burglar is a bloke in his mid twenties to mid thirties) and anyone with so much as an ounce of attitude or 'awkwardness'... which might just be shyness, but I'd rather be safe than sorry. I'm a little more relaxed in hotels on tour. Even the smallest instinct of 'there is something weird/not right'...go with it. Think about trying to encourage with your price structure smaller numbers of longer bookings to keep your footfall down.
Hiding money in weird places that they'd never think to look is a good one, and keeping all doors but for your work room door locked. I never thought about the handbag thing but thats a good idea.
But also remember that even though there are risks to be cognizant of, and take the steps to avoid the risk of, the risk is still relatively low of anything serious happening and your main 'bugbear' will be twat no shows and arsehole timewasters and most of those are just at home alone wanking themselves into an early grave, I imagine. I always try to remind myself of this when I'm feeling anxious etc