The video about how I converted another RC toy car into a camera equipped rover is online:

More details are on my pages:

http://homofaciens.de/technics-robots-R7-construction_en.htm

The weight of the the rover including 4 AA NiMH batteries is 500g:

The weight is not below the 500g limit which would grant the cheapest option for shipping, however it's clearly below 1kg which is my second option. There are several grams left for packing, a charger and add-ons.

Coming test drives will be used to optimize the software:

http://homofaciens.de/robospatium-controlstation-R7_en.htm