Texts on Principal Bundles, Characteristic Classes, Intro to 4-manifolds / Gauge Theory

You might find the following useful: G.L. Naber, Topology, Geometry, and Gauge Fields: Foundations, 2nd.. It has a specific aim and purpose though: it's oriented towards those who want to learn the math foundations for gauge theory within a rigorous setting. Maybe pure math students might like a more broader approach.

C.H. Taubes, Differential Geometry: Bundles, Connections, Metrics and Curvature (Oxford Graduate Texts in Mathematics) might also be helpful. ... It hasn't been released yet, but given the author's fame and stature I think it might be a good pick. ...

If you want to focus on four manifolds, don't forget the classic of Donaldson and Kronheimer, Geometry of four manifolds. It may be a tad on the advanced side, but does contain some information specifc to 4 dimensions not available in the other books you listed.