This is a Great song.
It looks hard to play, but if you play your A-E-D with your 3 small fingers crawling 1 finger at a time it is not that hard at all. Climbing the strings like a ladder from D to A and then to E will alow you to get to the B7 without moving your index. also it lets you slid down into the bars real easy.
Good Luck.
Grateful Dead - Attics of My Life