I'm not sure what I'm missing in my plot to take out Honest Abe. In case you too are looking for hints, I will use spoiler tags to share what I have done so far.
I got the beacon from Bosco's inconvenience. Next we went for a ride in the Desoto and tossed the beacon onto Abes back. Then we went to the War Room, chose Boscos and fired the misle. It took off, then a message was displayed saying "missle destroyed". BUT the beacon signal is still going. 
Can the missle not get a moving target? How can I get the missle to hit Abe? 
Any help would be great. Thank you.