There are flights from Manila to Naga with Cebu Pacific. Prices are very reasonable. Also there are fligths with Air Philippines.
Naga is about 2 hours from Daet by van.
Not far from the airport in Manila is Philtranco Bus Lines operating from Pasay.
PASAY - EDSA CORNER, APELO CRUZ STREET, PASAY (02) 851 8077 TO 79
Your best bet is taking their Aicon Service. It’s 560 pesos one way. There are 3 buses at night, leaving at 6:00 PM, 8:00 and 9:30PM. The bus runs direct to Daet and arrives between 03:00 AM and 05:00 AM.
There is also one at 08:00 AM which arrives in Daet around 16:00 PM. Check their website to see the current schedule.
Car – 4pax 4,000 PHP / 89USD*
Van – 12pax 4,500 PHP / 100USD*
Van – 12pax 12,000 PHP / 267USD*
Van – 12pax 8,000 PHP / 178USD*