Are usb pendrives/sticks random access?

Solution 1:

No, the access is not truly random since USB flash drives use NAND flash, according to Wikipedia:

With flash memory, only the NOR type is capable of true random access, allowing direct code execution, and is therefore often used instead of ROM; the lower cost NAND type is commonly used for bulk storage in memory cards and solid-state drives.

And:

NAND flash memory forms the core of the removable USB storage devices known as USB flash drives, as well as most memory card formats and solid-state drives available today.

Solution 2:

Reads should all take the same time. Writes are another matter; flash is split into fairly large blocks, and you have to erase all of a block before it can be written to.