Lens to pair with RP for travel

[Fast Glass]

I agree with Kayaker with the idea of a good general zoom. I don't view primes as a good option strictly by themselves. Unless you know exactly what works for you.

An ultra wide like a 14mm and a 24-105mm would be a good option.

Personally I have and love my 16-35mm and 85mm. Makes a good combo for me lately for a walk in the park.

But, if I had my way for a trip around the US and Europe I'd get the 11-24mm or 16-35mm f/2.8, 24-70mm f/2.8, 70-200mm f/2.8 IS II or III. If I had to drop one lens from that list it be the 70-200mm. But that's just me.

If I know I want to do some birding and wildlife I'd pack my 300mm f/2.8. It makes an awesome distant landscape lens as well. But I'd have a hard time justifying it if weight is even remotely a factor. Lol.

Hopefully that gives you something to think about and a wet stone for your mind.