Welcome, Morris!
Looks like you may be downsizing a bit- isn't a Keystone Montana a larger fifth wheel? The
Scamp 19D is a great choice. Another popular option is the
Escape 5.0TA, manufactured in British Columbia. The
Scamp has a side-to-side bed in the loft, while the
Escape has a longways bed. For some that makes a difference.
Escape previously made a slightly smaller single-axle 5er that is closer in size to the Scamp. It's no longer made, but used ones come up occasionally. Here's a link to one that
sold recently:
2013 Escape 5.0 Classic
Best wishes finding what will work for you!