Good choice, you should be well covered for travel then. I don't have the pleasure to own the 16-55, but it is really highly regarded in almost all reviews, probably the best APS-C standard zoom. Do remember to claim Sony cashback on both the body and lens if you have recently purchased them.
Ah the trusty 35mm is long gone I’m afraid, I figured if I was getting a bigger body anyway that was no longer pocket size, I might as well add a bit more versatility than a prime. Using the 16-55 now which I’m really enjoying actually.
Make good use of the Eye AF, you will forget your A5100 pretty quickly :) I certainly don't miss my NEX-5 which was super slim. If you enjoy using 35mm/1.8 OSS which I have too, then GR is definitely very different. I very often carry both of them.
I think I would definitely pick A6600 for travels. A6600 is tougher and weather sealed, battery lasting way longer (GR is ~200 shots each battery). It is hard to predict what to expect when travel, having a zoom will definitely help. I also feel GR needs a bit of babying because of the dust issue for the sensor. Eye AF on A6600 is also convenient for travel photos, not to mention the video.
Oh that's interesting to get your first hand experience of both, thanks. Maybe I didn't make the wrong choice then. I'll be honest I mainly use my camera on holidays or day trips, rather than dedicated photography outings. Sounds like the extra bulk of the a6600 may be worth it for my use then. I do sometimes miss my old a5100 paired with the Sony 35mm though, the size was just so great!