I'll chalk out your path for you- i.e. lay it down or plan it out as a carpenter or ship-builder plans out his work with a piece of chalk.
I can walk a chalk as well as you. I am no more drunk than you are. The allusion is to the ordeal on board ship of trying men suspected of drunkenness. They were required to walk along a line chalked on the deck, without deviating to the right or left.
The tapster is undone by chalk, i.e. credit. The allusion is to scoring up credit on a tally with chalk. This was common enough early in the nineteenth century, when milk scores, bread scores, as well as beer scores were general.
Chalk it up. Put it to his credit.
As good-humoured sarcasm, Chalk it up! is tantamount to saying, “What you have done so astonishes me that I must make some more or less permanent record of it.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894