my thoughts are with you runkid..
I understand about trying to get images out of our mind - my mum also died of cancer last year. She too looked awful at the end..
The best thing I found was to keep looking at photos of her (however hard it was) and eventually when I think of her I see those images not of her when really ill. But it does take some time.
Also re excutor etc - Take your time...
There is no rush... do it at your own pace..
My mums probate took almost 9 months to come through (which is longer than ave) and it worked in our favour as we had time to get used to her not being around when it came to selling the house etc.
Put yourself first, let yourself grieve, then worry about everything else afterwards..
You should be very proud of yourself for the way in which you were able to be with him at the end etc, not an easy thing to do (my brothers couldn't manage it with either my mum or dad)..
Cry loads, it does help (although make sure you have paracetomol around to help with the crying headaches)...
It does get easier honestly.. just go at your own pace...