solve the problem that use grid route

[Rariwa]

Hello,
I have optimization problem similar to TSP but I am thinking to solve it as sVRP.
The objective is to collect reward located at scattered location. Imagine the location search as simple as chess board where a worker can only move one grid/box per step. There are 2 levels of worker and reward where the highest level worker can collect all 2 levels of reward while the lowest level worker can collect the lowest level of reward. These 2 levels of workers have different cost rate per unit step. the starting point for all workers is same at certain position in grid. My job is to determine the number of workers along with their levels and the route that need to travel in order to collect reward within the total step as a constraint. My job is to optimize the revenue which is the collected reward subtracted by total cost. they don't need to come back to the original position like traditional TSP problem.
I would like to have suggestion and advice on how to build solution for my case using this repo. It is not convenient to use distance matrix to achieve the destination since the worker must step grid by grid.

Thank you