Post Gloucester:
A40 to A4136 - through Forrest of Dean to Monmouth
North A466 then B4521 through Skenfrith (The Bell is a fab lunch stop - bit pricey but excellent food) to Abergavenny.
Same thingy as wessie really but with a twist. Take the A48 from Chepstow, towards Newport. After the R-bout at top of a hill (sign posted to Caldicot/Portskewt) straight over and down the hill, turn RIGHT towards Shirenewton, through Shirenewton (half mile on) and take a look over your left hand shoulder after the Farmhouse OTR, views of Severn Bridge and Brizzol Carry on that road till T-Junction and follow Wessies run.
Keep revs low as there are a few lovely crest to take advantage of