At eNotes, we can't write your journal entry for you, but we can give you an idea on how to get started for this assignment.
The California Gold Rush lasted from 1849 - 1851, so consider that there were no highways, and all travel overland headed west was by wagon and horse (no transcontinental railroad yet).
Also keep in mind that very few people actually got rich looking for gold. Most made a living hand to mouth, with just enough mined to survive, so the attraction or the dream of the gold rush and its reality were very different things.
Mining camps, or "boomtowns" had greatly inflated prices on everything, because miners couldn't leave their claim to go to the city for supplies, and they needed the tools and food right away. This was very profitable, and was another reason why few miners got rich.
The links below have some good resources to deal with the various aspects of your assignment.