Showing House With Current Tenant Issue ... Washington

[Account Closed]

So I have a tenant moving out at the end of the month and is not open to allowing me to show the house to pre-screened potential tenants in a supervised fashion with a totally flexible schedule.  I explained to her that she needed and got the same cooperation from the previous tenant but is unwilling to play ball.  The next go around I am adding verbiage in the lease to avoid this as much as possible.  I am considering posting a 24 and 48 hour notice for entry and threatening or executing my rights under RCW 59.18.150 (6) Washington State Residential Landlord-Tenant Act, provides as follows:

“The tenant shall not unreasonably withhold consent to the landlord (or manager) to enter the dwelling unit at a specified time where the landlord has given ... notice...”

for un-cooperating tenants.  I know it's unlawful to deduct the deposit for days she has off the market although other do.  

Any advice on 

(1) how other avoid this scenario in there lease and 

(2) how to proceed with the current tenant.  

Thank you for your consideration.