We must have the same dog. Duchess does the same thing except she only gives me about 10 minutes to unwind before the whining starts.
As far as how much she can walk.....we when first start our walks, she is super hyped but after about 30 minutes, she will slow down.
My last yorkie just came to a complete stop when she got tired but Dutch is hyper energetic and will walk until she drops dead. When she starts slowing down, I will pick her and carry her for a little while depending on how far we walk.