Welcome to the forum Anthony,
I think you are very brave to walk the 1600km in winter. Although this sudden cold front is unusual for October, it'll be a good thing to keep an eye on weather posts from now on to give you some idea of what might be in store for you next year.
You will arrive in Santiago in a Holy Year so that qualifies you for walking in a Holy Year. By the way, you don't have to walk to Santiago to qualify for the plenary indulgences. This is what the Archdiocese has to say about being granted the indulgence:
Conditions to gain the Jubilee
1) To visit the Cathedral, where the Tomb of Saint James the Great lies.
2) To recite a prayer (such as the Creed or the Lord's Prayer praying for His Holiness the Pope). It is recommended to attend the Pilgrims' Mass.
3) To receive the Sacraments of Confession (it may be 15 days before or after) and Communion. Both are responsible for the conversion and the compromise of love to Jesus and our brothers. This is the heritage of Saint James.
The grace of the Jubilee is basically a plenary indulgence for the forgiveness of the punishment our sins deserve.
Indulgences: The Canon Law Code defines them as follows (ch. 992):
"An indulgence is the remission in the sight of God of the temporal punishment due for sins, the guilt of which has already been forgiven. A member of Christ's faithful who is properly disposed and who fulfils certain specific conditions, may gain an indulgence by the help of the Church which, as the minister of redemption, authoritatively dispenses and applies the treasury of the merits of Christ and the Saints."
In order to understand this, we must distinguish between guilt and temporal punishment.
"An indulgence is partial or plenary according as it partially or wholly frees a person from the temporal punishment due for sins." (ch. 993)
The grace of the Jubilee - fulfilling the required conditions - is a plenary indulgence. "All members of the faithful can gain indulgences, partial or plenary, for themselves, or they can apply them by way of suffrage to the dead." (ch. 994)