Would it be appropriate to have a Host Wanted sub-forum, like the Companions Wanted sub-forum?
A tourist could then post his/her tentative schedule or itinerary in the post and hosts could proactively respond with invitations. This could save a lot of effort (and sometimes frustration on rejections) to the tourist. I have already seen hosts spontaneously reply to Companions Wanted posts with invitations to stay with them when in their town.
So, e.g., if one wants to travel from SFO-LAX via the PCH, one could post a host wanted ad with the title "Traveling from SFO to LAX" and prospective hosts could reply. One could then respond with hosts with acceptance response or decline if multiple invitations occur or for any other reason.
I hope that creating a sub-forum will not incur serious development effort it this would be worth a try if found acceptable and appropriate by the governing body.