So ... like you I live in CO - opposite side on the Western Slope - lots of mixed riding here as well - and as others have said - personal preference and riding style will dictate your choice ... keep in mind I ride solo in remote areas in the West regularly - no easy help / cell service, etc. and a conservative and intermediate level of skill off road / typically ride loaded with light weight camping gear in travel style ... here's my take

1. Currently have a DL650 - Awesome Road and gravel road bike solo and 2 up - as you've experienced - dangerous for anything challenging off road for my skill level and areas of back-country / available help, level of confidence - no fun to pick up off road - but bike is well set up to crash - loaded for travel with top box and soft panniers ... around 535-545#

2. Had a DR650 - DR was ok solo - better road than off road for me due to skill and the weight - although have to say and have seen this bike to be very capable off road in the right hands - just not mine - limped my way through the White Rim Trail in Moab loaded up a few years back, SAND kills my confidence even after several trainings ... cramped 2 up and not used this way very often by me - had all the usual mods to make it dirt worthy/ travel ready and "crash-able" - still a bear to pick up when napping, especially when loaded for travel - rear rack (no top box) and soft panniers - about 405-410#

3. Had a KLX250 - under powered for altitude - but easy off road and easy to pick up ... you are a slow moving target on the road with the 75 mph zones out by me - fully loaded up for bike camping and travel - topped out @ 65mph jetted and piped ... around 325-335#

4. And the winner for solo riding / travel / and off road ... my other bike ... a lightly used / lowered 2007 DRZ400S - not as good for long highway slogs as my DL650 the DR650 or your CBX RR choice; not as light or easy to pick up as my previous KLX250 off road - but easier by far than either of your choices - a whopping 46# lighter than the DR650 - your CBX RR splits between your old DL and the DR ... DRZ, fully loaded w/ bike camping and travel gear - soft panniers and rear duffel... around 340-355#.

For Me - the DRZ is good enough for a steady hour or 3 to safely travel on the posted 75 mph highway around me to get to dirt or gravel - it is buzzy at this speed, but manageable and I accept it - and - for my style of solo riding in often remote areas - a goldilocks between my DL650, my old DR650 and KLX250. Jenny @ Rally Raid makes the CBX RR look easy in all the "Hard" places I ride - as do others on their DR650's - that wouldn't be me ...

Overall Cost to achieve your mileage goal I think would be fairly equal - though it would be 1 CBX RR package or 2 fully done DR650's or DRZ400's for similar distance.

Gauge your Confidence, Skill and Where you want to go - pick the bike that covers the aspect of holding that confidence in the least desirable circumstances for your skill and is the least objectionable in it's area of weakness for where you want to go ...

Best