This is an interesting idea. In fact I faced a similar problem recently - I wanted to pick up a sofa that I'd bought from ebay.

My options were - borrow a big van and drive it there and back, hire a man and a van to do so.

I chose the man and the van via this service - https://www.anyvan.com/

So a solution already exists here but perhaps there's a spin on it? Get people to pick up your items when they're traveling that way anyway - it's been done too - https://www.nimber.com/

It maybe that your market isn't mature and there's a need for this where you are.

What I'd suggest is the following:

Sketch out the problem/s and what people do about that problem
Sketch out the use cases
Sketch out all your assumptions
Then try and debunk them - one by one
Speak to people - whether that be on forums, facebook, in person, friends, relatives etc and gain as much insight as you can.
Once you've got that insight try and sketch out the solution to the problem
Once you've got that - then go back to your BMC and re-hash the whole thing
Then build a cheap website/landing page saying that you can solve that problem by doing xyz - you don't even have to have the service or anything
Promote it and collect feedback
Re-hash the BMC
Then decide whether it's viable or not.

Happy to chat through in more detail.

This is a great question and a situation I've faced a number of times.

Start with your own strengths, where you add value and where you want the business to go.

Then build out what you don't want to do, what you want to keep control of and what your ideal person looks like.

From experience I'd say that you need 2 people to run the agency - one who's operational and the other who's in charge of client strategy and client relations.