Janesy - plenty of big hills to go at round here Some suggestions:
1. Beddgellert, Pen-y-Gwryd, Capel Curig, Betws, B road down the valley, Conwy, along the coast to Glasinfryn (there is a traffic free cycle path and quiet lanes all the way parallel to the A55), back lanes via Pentir and Penisarwaun to Waunfawr, back to beddglert
2. Beddgellert, pen-y-Pass, Llanrug, Waunfawr, Bontnewydd, cycle path to penygroes, Nanttle, Rydd Ddu, Beddgelert
3. Beddgelert, south on A498, then A4085, R on B4410, short section with cycle path on A487, L on A496 to Blaenau Ffestiniog, A470 over the Crimea Pass, back lanes parallel to A5 to come back over the Migneint either via Cwm Penmanchno (steep climb on B4406) or via Ysbyty Ifan (B4407) to Ffestiniog, then B4391, and back to Beddgelert
4. Llyn Peninsula route: Beddgelert, tremadog, Criccieth, aberdaron, Nefyn, Clynnog-fawr, Penygroes, Nanttle, Rhyd ddu, Beddgelert
There's lots more hard steep climbs up back lanes, bit harder to navigate round, but if you want company then let me know and if I'm free I'll join you for a ride one day.
Enjoy - its an ace place to road ride