Formula for multiple data points and references

I am looking for a formula that I am not sure can be done. I have attached a picture of what I need basically. I have two sheets in a worksheet. One contains a reimbursement for travel. The other has the data with the miles it is from Point A to Point B. I want to be able to put in Location A and B, then in the line below the number of miles it is based on the data. Location 1 and Location 2 change from cell to cell.
Please see attached if you can help me.