Do I get to declare HQ Mole before watching the first cards I'd access anyway?
There is no official rulings, because an official (Wizards of the Coast) hasn't yet ruled.
The last official rules errata was v1.7 from March, 2000.

March 11, 2000 - Netrunner Rulings, v1.70 - Author: Top Runners' Conference   List of official rulings used by the Top Runners' Conference. It is compiled primarily from rulings made on the Netrunner mailing list by representatives of Wizards of the Coast. Covers Limited, Proteus and Classic.

The next official rules errata v1.8 has been stalled, you can read the discussion thread here. There is errata concerning the Moles cards, but I do not believe that WotC has provided an official ruling regarding the matter within their mailing list.

D. all topics concerning errata and clarifications discussed on netrunneronline, but maybe not completely validated.
D10a. HQ Mole - ... Clarification: HQ Mole triggers during the “access cards” phase, and can be used anytime during this phase access. When Runner has HQ Mole installed, he or she may first access the card(s) normally accessed without using HQ Mole, processing any immediate effect that would occur due to this access (like the 2 Net damage of Setup!). After that, he or she may still trigger HQ Mole to access the additional cards.
Similarly, when Runner has multiple HQ Moles installed, he or she may use them one by one (and processing for each Mole any immediate effect). In other words, Runner is not required to declare at once how many HQ Moles will be used, but can decide after each HQ Mole used, if he or she will trigger another one.

It is possible that WotC hasn't ruled on the matter, but netrunner online (not official), may have come to a decision. This can be observed on their rules page.

67 HQ Mole - When Runner has HQ Mole installed, he may first look at the card(s) that he would access without using HQ Mole, and after that, he may still trigger HQ Mole to access the additional cards. In the same sense, when Runner has multiple HQ Moles installed, he may use them one by one; i.e. he is not required to declare how many HQ Moles he will use already when his run is successful. When Runner has finally decided how many HQ Moles he uses and after looking at all the cards stored in HQ that he will access, he decides in which order he accesses the cards. As always, he may intermingle with upgrades accessed from HQ.(–Netrunner Online)