If you don't have a use for the Nikon SLR now, before you leave, then don't buy it. An SLR is not a "vacation camera". Yes you can use it as one but the SLR is best used when the purpose of being some place is photography.
I notice you are not even asking about lenses, that is what counts. No one would know if you used a D7100 or a D5300 or a D3300 body by looking at your photos. But the lens would make a difference. and if you used a tripod would make a different (mainly because of the improve time, care and composition in each shot.) If you have a fixed budget for the entire system go for the less expensive body so that you are not skimping on the glass.
No one can give specific advice until you answer these questions
- What are you planning to take photos of?
- What will you do with the photos (make large fine art prints, place them on a web site. Store them on your phone,...????)
- What is your level of experience with photography?
- What is you budget for Lenses? (the body is the smaller half of the system.)
I think the advice you are getting to get a smaller system is correct. A high-end compact camera would work well too. The Canon G series is good or something else along those lines.
For travel I like to use a pelican case. That way I don't have to baby the gear or hand cary it around. Those case survive a roll down a stairway, falls into water or whatever. I place a soft bag inside the bare hard case with no foam. Then I have a bag to use
DOn't think as a new photographer with a new SLR system you are going to get photos of wildlife close up, eagles in flight and a close up of a moose. Those take all day of waiting and hunting with a long ($2,000+) lens on a tripod. For quick snapshots the smaller compact will do because that is the one you are carrying.
Before you leave, starting today, try and shoot 100 frames of "travel photos" in your home town within 5 miles of where you live. The BEST photos are always the one you take closer to home because you know the area. Then every day run those 100 frames through your post processing work flow and select the best 5 or so shots. Think what could be better, give your self a new self assignment and go shoot 100 more. Maybe you have a Farmer's market and want to tell a story about it or there are flowers at a local park. There are birds near you too. The best times are always close to sunrise/sunset. Really, do this. Shot a few thousand "serious" travel photos BEFORE you leave home. One good assignment is to look at a travel magazine and try and copy the photos close to home. Advice? (1) get closer, (2) repete the last step a few times, (3) don't bother to shoot if the light is not "right", (4) check the background and all four edges of the frame. There are 100 other things but those are the ones most people forget. After those first few 1,000 frames it states to become second nature.