Arrgh! Just seen your post.
Sorry, I have been away in France on a mercy mission and only got back last night.
I know Hortas de Tabual well.
I have clients at Ingrina. The PT phone line runs from Vila de Bispo, then Raposeira and then Hortas. You should, as you note, be able to get SAPO ADSL over the landline in Hortas although the data transmission speed over the landline may not be that great.
As regards using a Vodafone dongle do not be to hopeful. With the folds in the hills around Hortas 3G reception is patchy at best. I suspect that even with a 12m usb cable the signal may not be that good. Furthermore, with the damp in winter and heat in summer, signal performance will be affected. This summer, I tried a vodafone dongle installation with a 12m cable, at the client's insistence,near the Ingrina Township over the hill from Hortas. The performance was not that great and was patchy.
As regards work, as you are a biochemist, you may find it worthwhile making contact with the University of the Algarve in Faro which has a marine research centre.
If I remember correctly, there used to be an English couple who lived in the big white round house above the restaurant at Praia de Zavial just down from Hortas who were marine research scientists and affiliated with the University of the Algarve. I have had a quick look through the Phone Directory but for the life of me cannot remember their names.
There have been a few marine research projects going on off-shore the Algarve and I would think there may always be a need for bio-chemists.
Also get in touch with Zoomarine in Guia as they have a R&D section as well I think.