General aviation pilot reported that the FBO failure to provide guidance and lack of signage resulted in confusion and a movement area excursion at BUR.

Narrative

After landing I cleared runway 8 per guidance of Burbank tower to taxi on runway 33; then left on D; right on B into the ramp. After turning left on D and right on B I looked for a line crew to marshal me in to the FBO ramp. There were many aircraft on the ramp and the path into the ramp was not obvious. Just in front of me I saw a truck between two rows of aircraft that had a flashing bar on top of the truck; which I interpreted as a 'follow me' truck; absent any other guidance. The 'ramp' did have a double yellow line; which I passed and then when I realized it was not a movement area I stopped. The truck with the flashing light bar was not a marshal truck. I called the FBO for guidance; but no one answered. I waited until an FBO marshal appeared; and then followed his guidance. Eventually Burbank airport operations came out and led down what was a road with aircraft parked on both sides to a parking spot. My mistake for not holding short of the road. Given the fact that the road had aircraft parked on both sides made the road look like part of the ramp; and other than the double lines there was no signage for aircraft not to enter. From a safety perspective it would be useful to put cones or other identification on the road. Further; when the ramp is packed full; a sign that indicates 'FBO this direction' would have helped as there is no way to see the path to the ramp; again given the sheer number of aircraft packed on the ramp. No question; my mistake; but since the FBO knew my arrival time they should have placed the marshal cart where it would be visible to me entering from the taxiway. This would avoid confusion such as I experienced. Burbank ground could also be helpful in this context. Why were there aircraft parking on both sides of the maintenance/access road? VNY has a runway closed and a large number of aircraft have relocated to BUR. To accommodate all these aircraft the FBO has parked many of them on both sides of this row. This was a contributing factor to my confusion.