There are many reasons given why Abraham was not informed what his final destination would be as he embarked on his journeys. To me, there is a very important lesson in both instances: When we were born, we embarked on our lives without any real knowledge or assurances of where life would lead us. In the same manner, all journeys and programs which we undertake are shrouded in mystery regarding their outcome.
This was not a problem to Abraham. He never felt alone or abandoned because he always walked with G-d. We, also, should be strengthened by the faith that if we try our best to walk in the "straight path", G-d will assist us in reaching the goals which we seek to attain.