Mt Sill and North Palisade would give you the toughest time. I did those when I was younger and bolder.
Mt. Sill from the south isn't that bad. Nice
day hike over Bishop and Potluck Pass 
Some tricky moves at the very end, but otherwise nothing super challenging (Potluck Pass is a good test of your abilities before the final climb). I always wanted to combine it with the High Route section from Palisade Lake to Le Conte, but so far have not been able to squeeze that detour into any hike.
pictures of a climb from the south
here 
