Go easy on the neck stretches. I wouldn't add any weight, or do any boxer/wrestler type weighted neck rolls -- at least not without consulting a specialist, and even then I'd take weeks or months to build up to it very gradually. We ain't kids anymore and don't rebound well from serious neck and back injuries.

Due to a C2 injury I'll never be able to ride a bike with drop bars at or below saddle height. For now I can just about manage bars slightly above saddle height, and it took months to build up to that from elevated riser bars. I still need to do gentle neck stretches before and after rides, and often soak in a hot tub of epsom salts.