We fly out of Seattle and stay either in a Marriott Towne Place or Springhill Suites about 10 min from airport. They let you leave your car for free for as long as you're away, and just charge you reg. room rate- not a jacked up park & fly rate. Air port shuttle. Free breakfast.
As it's a chain, they may have one or both near BUF.
The ones in Seattle have Ent. Book discounts too.
Last year we were away for almost the entire month of Aug, and was no problem leaving car. Secure lot, security guard patrols.