Advice for starting point near the border (Tui/A Guarda/Caminha)?

Where are you starting from? Moscow?

In Spain you easily can forward your luggage from a postoffice ( correos ) to e.g. Ivar, owner of his forum. There are many threads about this matter on this forum

You could start in A Guarda or Tui.
Collect your first stamp on your credential and collect two stamps a day to be shure you can apply for your Compostela document once you are in Santiago.
Condition is that you walked the last one hundred kms to Santiago and two stamps a day.
Both A Guarda and Tui will do. a Guarda is even more than 100 kms away.
Tui is the starting of lots of pilgrims, mostly from Spain.
From A Guarda it is very quiet untill you will reach Redondela where the Coastal caminho joins the Central Portuguese caminho.
You do not tell where you fly into . If it is Porto you could take the ALSA bus from Porto (Stop Casa da Música) to Vigo and then take the bus to A Guarda

To Tui you can take the train from Porto to Valença do Minho and the advantage is that you have a nice walk through the Valença fortress and a beautifull view over the Minho river and Tui in the distance and as a bonus the walk over the famous bridge , built by George Eiffel, also welknown from the Paris Eiffel tower.

Bom caminho

You can start from Baiona which is 130 km from Santiago. A Guarda is 165km away. There's a good bus service from Vigo to Baiona see http://www.atsahorarios.com/