Hi David,
I have no experience with Slime+Windows, but have run Ltk with Clisp on Windows (withtout slime) successfully. Unter Unix/Mac OS I am running Ltk under slime without any problems. As for an alternative to the ActiveState Tcl, please try tclkit: http://www.equi4.com/tclkit.html To use it, just download the exefile and set *wish-pathame* to point to it, eg:. (setf ltk:*wish-pathname* "c:/whereever/itmaybe/tclkit.exe") and then try to run Ltk
HTH, Peter