Deductions & credits

If a salesperson visits a client 10 miles from the office those miles are deductible. 
What if the sales person (who lives 50 miles from the office) visits the client first, prior to coming into the office, do they get to deduct the greater mileage?

what if the same salesperson (who lives 50 miles from the office) visits a client very near the office, however, the sales person never goes into the actual office, can they deduct 100 miles using the temporary workplace rule?