Kerckhoffs (part 1) Mystery Cache

This is a puzzle cache. Please do not go to the posted coordinates, nothing is hidden there.

As a young kid Cacher Craig set out to create his own method to encode data, as one does. Of course he didn't yet know about the design priniciples of proper encryption algorithms like AES or ECDH or whatever, instead he had simple things like Caesar Ciphers as his model. In an effort to create the most complicated variation of this possible he came up with:

1. Each letter maps to a string of digits (called a "codeword"). These codewords have different lengths. The first digit tells you how long the codeword is. (For example "52381" would be a valid codeword because it starts with 5 and is five digits long).
2. After you replace a letter with a codeword the entire mapping shifts (letters stay in place, codewords shift down). The amount that it shifts is given by the last digit of the codeword. (For example, using the key below, if the first letter of the plaintext is "A" it would map to the codeword "89411894". If the second letter were "S" it would now map to "57643" since the entire key has shifted by four). This shift is cumulative. Codewords that shift off the bottom go back on the top.

Cacher Craig had various other tricks that would make this even more confusing. The same letter could appear multiple times in the mapping with different codewords. The letters might not appear in alphabetical order in the mapping. Other symbols like punctuation or whitespace could also have entries in the mapping. Finally shorter codewords could "hide" inside longer codewords (such as having both codewords "321" and "53214") to confuse frequency analysis. None of these additional countermeasures will be employed for these puzzles (at least intentionally, all keys have been generated randomly).

8505360071710319463201224502636187376700406263844057643636187717103197155979336129523
8193042440445044502376923921735894118944502450293042440485053600717103171710317004062
7004062446845024468700406292392173553177446884524991209715597934504376930424404446885
0536006361878744591845028852739171710314468850536004502361450445048941189423450488527
3919239217352944688941189488527391446863844045026924738452499171710314254446863844097
1559793450242547004062576436384402087445918576433614502885273916361879239217355764329
9715597936924733762336171710318505360020850536007171031930424404238505360063844063618
7874459184502885273917171031446885053600450236197155979385053600845249915238157643531
7737689411894450242546384403767004062692473692473236924739463201229463201224504450252
3816384404468930424404576436361876384409715597937171031425457643376971559793700406288
527391946320122

Thanks to OohLookItsARabbit for test solving.

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