Keyston Bullet Slide Out Leak

Our Keystone Bullet is leaking from the from corner of the slide out. Two weekends ago it was not raining but the AC condensation runoff was enough to cause water to seep into the camper from the corner of the slide. I found nothing wrong with the seals on the sides of the slide out after my thorough inspection. I extended the slide a few inches to investigate the top seal and found that the caulk has been compromised and there are few areas between the side of the camper and the seal where water can definitely penetrate. Furthermore, I noticed the low point of the roof gutter is exactly over the area above the seal that has significant degraded caulk. Water must be building up in the gutter and dripping over the side of the gutter then down the side of the camper and eventually seeping though the degraded top seal caulking and into the camper. See the pics below.





I'm going to scrape and clean off the old caulk and re-caulk the entire top seal. My questions are:

1. What caulk/sealant should I use?
2. Thoughts on sticking a strip of the 3M EZ gutter just above the top seal after it's re-caulked to direct all water running down the side of the camper away from topseal?
3. Any other suggestions?

Thanks in advance.