It really is a wonderfully prayerful experience, and there is something incredibly moving about adoration during the "silent watches of the night." In fact, after the end of the Quarant'Ore, there is a palpable sense of loss as Our Lord is reposed in the tabernacle. I imagine that a similar sense of loss would have been experienced by the disciples after the Ascension.
There will be Missa Cantatas on Friday (8pm) and Saturday (10:30am) but the church will be open for people to come and spend a little time with Jesus in the Blessed Sacrament right through the Forty Hours. Not everyone is in a position to be able to watch through the night, but most of us can spare 20 minutes at some time during the day...
If you feel the need to recharge your spiritual batteries, then directions to Our Lady of the Rosary, Blackfen can be found here. If you'd like to know a little more about the devotion, then Zephyrinus has a great post on it.