I am so sorry for your loss. Losing my father in 2005 was the very hardest thing I've ever gone through, and the darkest time in my life. I couldn't even get on my bike for about 9 months after he died, and even when I did, I couldn't ride on the road initially. He died in a car accident in a tiny Honda Civic he'd driven for over 10 years, and I felt so vulnerable on my bike after that. I would only ride my mountain bike on trails for a long while. I finally did start riding on the road again, but like you, I cried quite a bit as I logged miles -- I too think and contemplate when I ride, but it was actually cathartic and helped in my long grieving process, I think.
A couple of years later, a man in my bike club died -- also in a car accident -- and he had been almost like a father figure to me, so that brought the tears and grieving back as I pedaled along.
I salute you in your resolve to complete your planned tour and am sure your father would be very proud. It will do you good, I just know it.
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow