it would be a bit difficult to do both lion safari and junagadh sight seeing togather. one idea would be finish somnath darshan, hire a car, go sasan gir (devaliya) there they have arrangement for doing a lion safari in forest deptt bus. you can finish that by say 1 pm and than move on to junagadh and reach by 3 pm, finish sightseeing there and catch the somnath okha express from junagadh itself. you may have to change the boarding point to junagadh. the train would be reaching around 10 pm at junagadh and therefore, you would be having ample time for junagadh sight seeing.