Bikaner Experience: We used it as stop over on our way back to Delhi from Jaisalmer. Dholamaru RTDC hotel is decent place to stay and food in their attached restaurant is too good. Junagad fort is worth visiting. And also go to camel research center. You may wish to skip Lalgad palce museum. But never miss the Ganga museum - there you'll some rare pieces from early Gupta and Harappan age.
Food, sight-seeing and shopping: For shopping goto KEM road - it's near railway station. And on your way you'll get plenty of bhujiyawala. Do test ghewar.
Activities & things to do: Visit Junagad fort and camel research center. You may also go to Gajner palace.
Travel tips, How to reach, travel warnings etc: From Jaisalmer chose day travel - you'll see lot of dear, peacock, neel gai etc.