I guess it's time to contribute my 2 euros' worth. I think Tomar is a very good location to consider for someone wanting to host a "south-half" Portuguese caminho albergue or guest house.
As I've mentioned, we'd bought here in Vila Nova da Barquinha, with the peregrino route to Atalaia visible at the bottom of our garden. I had thoughts of a hostel here. But--after watching pilgrims walk by, now in almost every season, I realize that there really isn't enough potential to warrant more accommodation here than already exists. And our local church-based group is, I think, working on a small lodging to augment the three hotels here in town, so our offering would definitely be more than the town needs.
It's the wrong place. The general pace and breaks in the caminho to this point (Barquinha) typically have people stopping in Golega, or thereabouts, the night before. We see most of our peregrinos coming by between 9 and 11 in the morning. Most people have limited time for their caminho. So why stop here in Barquninha, for the typical walker, when you can make it to Tomar, and then spend a lay-day there and see the splendid sights?
Tomar is the obvious day-off point for peregrinos/as who are not in a hurry. And much of Tomar's accommodation is going upscale, with new and rebuilt 3- and 4-star hotels. So friendly, moderately priced accommodation--perhaps on the quieter, eastern side of the river rather than in the quaint but pricey old town--could be a good strategy. There are some attractive little areas over there, with the property likely better priced than in the trendy old town, but still not very far, walking, from the heart of town where the restaurants and cafés are, and where people tend to congregate in the evenings.
I'd say it's worth checking out!