I haven't done the C2C from Whitehaven to Sunderland (Hadrian's Cycleway) and did The Way of the Roses (Morecambe to Scarborough).
However
@gam001 has done it from Carlisle to Sunderland on a road bike (albeit he might have used some of the adjacent roads rather than the tracks). I think he really enjoyed it. I recall he sais there's quite a few rolling hills but nothing too steep. Hopefully he will be along shortly.
I have done Hadrian's cycleway from Ravenglass to Whitehaven which was great, albeit not really suitable for road bikes.
Hadrian's cycleway from Whitehaven is on my to do list funnily enough, not least because it can be done on a road bike.
@400bhp has pretty much remembered everything there - quite impressive given I told him about it back in 2010!
Carlisle>Gretna>Tynemouth - I did it solo on a hybrid w/ 25mm road tyres - just did it "for a laugh" and absolutely loved it
Did it 1 week after doing a shortened "Way of Roses" C2C (210km / 10k feet of climbing with
@400bhp) and 2 weeks after my first (flat) century ride
This ride was a nice balance of distance / scenery / small & rolling hills - will definitely do it again at some point (next time family stay in Tynemouth?)
Travelled on fairly quet roads (except briefly when near Newcastle), just above the A69 - pretty much all road, few tracks
It was just shy of 100 miles, took it fairly easy and stopped at around 35 miles & 70 miles, did it in around 7 hours including stops
I have a gpx file / cafe stops info / list of what I took with me - very happy to email all to you if you are interested and PM me your e-mail address
If you slowly build up your stamina before you go and take the right kit with you, you'll really enjoy it
(EDIT - you can look at the gpx file on screen before you go if you don't have a gpx device on your bike.)