A: Yes, it is possible. Instructions are as follow:

1) Categories.

Replace file categories.txt under cgi-bin/ppcal_data/

Each entry should start from new line and it should have the following structure:

CATEGORY NUMBER|CATEGORY NAME|NUMBER OF PARENT CATEGORY

For example:

1|First category|1
2|Second category|2
3|Third category|1

Will translate into the following hierarchy of categories

First category
First category > Third category
Second category

For the Top level categories NUMBER OF PARENT CATEGORY should be the same as
CATEGORY NUMBER

2) Items.

Replace file items.txt under cgi-bin/ppcal_data/

Each entry should start from new line and it should have the following structure:

CATEGORY NUMBER|CATEGORY NAME|IS ITEM ON|USER NUMBER|ITEM NUMBER|ITEM
NAME|PRICE|WEIGH|QTY IN STOCK

For IS ITEM ON: ON=1, OFF=2
USER NUMBER = 8001
ITEM NUMBER has the following structure: 900 + consecutive number. For example,
9001, 9002, 9003...90010, 90011 etc.

Examples:

1|FIRST CATEGORY|1|8001|9001|FIRST ITEM|49.00|0.25|100
2|SECOND CATEGORY|1|8001|9001|SECOND ITEM|49.00|0.25|100

RECOMMENDED METHOD of creating bulk files:
Use MS Excel and keep corresponding fields as separate columns.

Copy Excel table into text file. Use replace function and replace "TAB" with |
sign automatically.