I'm using running to help burn some fat mostly because it is the only cardio I really enjoy doing. I know muscle helps burn fat faster. Would using a kettlebell between runs help promote fat loss, lean up, and get my pace higher on my runs?
Any proper weight training program will help 'toning up' and weight loss. For a better run time a lot is dependent on the type of run (long/short distance) and what is holding you back from improving through running itself. To be a better runner, you have to run - you might consider doing sprints (Tabata protocol or any that fit your needs) for endurance or plyometric training for improved explosive power. A good overall weight program will help build strength and endurance throughout your body potentially reducing lack of endurance or power by building up supporting muscle groups.