Long term research plan
First, get tenure. If your current path works for that then you have time for the longer run. Get that done. 

But one of the ways to build a long term research program is to do it in collaboration with others. If you have a few people (three is enough) in your department that share research ideas in general, you can form a weekly seminar that meets for an hour and discusses "things". Those things can be recent papers or wild ideas that might develop over time into something significant. It may be a help if some of the members have been around for a while. Even quite intractable problems can be discussed on occasion as long as it doesn't get bogged down. 

It is also useful to include students (at any level) in such seminars. You don't need elaborate procedures for academic credit for such things. Just an informal meeting. Students presenting papers to the group is possibly worth doing. 

Of course you should work out authorship questions early when you start to work seriously on something that will lead to publication. Fighting with colleagues over the order to list authors is a good way to destroy such a seminar.