Hi Tank63,
As vickster says there's no real substitute for getting to some bike shops and trying them out because only you know exactly what you're looking for in terms of feel for the type of riding you want to do.
I must admit that I've not ridden a Cannondale and so I'm sorry but I can't give any personal experience of the CAAD range. Looking at websites and the Cannodale CAAD bikes they seem to cover quite a range including different builds as well as different frames because some seem more road focused whereas there are also cyclocross options in the range. The prices also seem to vary from about £800 or £900 up to about £2,500 and I've no idea which CAAD you're looking at buying or what you're budget is.
You've mentioned that you want a bike that can cope with canal paths, gravel and cross country but also be responsive on the road. I guess that any bike is going to struggle to be perfect at everything and potentially the more able it is off road the more compromised the on road experience is and vice versa.
However just in case you do want some ideas of other bikes to consider against the Cannondale options maybe some of the following would suit. Some of these will be more suited towards off road than road and some others the other way around but the best way to find out if they're right for you is to try them if you can.
If you were looking at the top of the Cannondale CAAD range and money is no object then you could consider one of the Mason Cycles bikes and perhaps the Bokeh with what you have in mind although I'm sure that the Resolution is a very capable bike in many situations as well.
https://masoncycles.cc/shop/categories/bokeh-bikes
The Shand Cycles Stoater or Stooshie
https://www.shandcycles.com
If you want to go for Titanium then there's the Spa Cycles Elan.
https://www.spacycles.co.uk/m1b0s21p3553/SPA-CYCLES-Elan-(105-11-Speed-Hydraulic)
After some advice on here I got a Kona Roadhouse (
http://2016.konaworld.com/roadhouse.cfm &
View: https://youtu.be/ltLN1bOXS10
) the 2016 model and I absolutely love it! I use it mainly on the road but it's the back roads of East Anglia and they're often either dodgy surfaces with loose chipings or covered in mud & dirt which has been dragged off the fields. My bike takes wider tyres and from my own personal standpoint it's a great bike. However I think that I was a bit lucky because I got a 2016 model with a big discount on the RRP which was £1,700 at the time when then 2017 models came out but with the 2017 model they introduced some spec changes and the price jumped to over 3k so I seemed to get lucky and buy at the right time. However there are still some options in the Kona range. The links below are for the 2018 bikes but if you search you might find some current bargains on the 2017 versions of their bikes.
http://www.konaworld.com/wheelhouse.cfm
http://www.konaworld.com/rove_st.cfm
http://www.konaworld.com/rove_nrb.cfm
Introduction to the 2018 Kona Rove range and a focus on their 650b wheel options:-
http://road.cc/content/tech-news/22...rove-adventure-bike-choice-steel-or-aluminium
Something from The Light Blue range of bikes either the Robinson or the Darwin :-
http://www.thelightblue.co.uk/Sport/5LB5RV62O/Robinson-Rival-1x
http://www.thelightblue.co.uk/Sport/5LB5DV12Z/Darwin-One-By
http://road.cc/content/review/174276-light-blue-robinson-rival-1x
The Fairlight Cycles Faran :-
https://fairlightcycles.com/faran/?v=79cba1185463
Wold Cycles Elm :-
http://www.woldcycles.co.uk/bicycles/production
Something from Bomtrack Bicycle Company and they've got a few different build options of their Hook. Although they won't be widely available it depends on where you are as to whether you're close to one of their distributors and according to the distributors website they're available from bike shops in Yorkshire, London, Oxford, Ipswich and Swanage.
http://bombtrack.com
http://bombtrack.com/bikes/hook-1-2/
https://www.lyon.co.uk/outdoor/bombtrack-uk-stockists
Or if you want an aluminium option then there is the Orro Terra range of builds :-
https://www.orrobikes.com/bikes/adventure
Good luck with your bike search and hopefully you can get some test rides on a few bikes to either find the right CAAD for you or something else that suits the type of riding that you have in mind.
John