But to provide more of a "big picture" overview for the different race venues thereby allowing you to compare/contrast them more easily, without referencing the detailed course layout pages, here are some descriptions.
"The Beast" @ Berkshire East
[For 2018, significant changes pending from ski resort's planned expansion to NE face of Mount Institute.]
By far the most eclectic and transition-intense venue!
As if prior years weren't eclectic enough, the 2017 course included skinning up open ski trails, closed ski trails, mountain bike trails, purpose-cut skintrack in the woods, work roads, and underneath a lift for maximize visibility (try to pass the lift riders!).
All the skinning is on very efficient grades.
Two bootpacks: both STEEP!
The skiing is steep but usually groomed (unless the Liftline and/or Beast trails are open, which they usually aren't at this time of year).
And since the shortened course option skips all the bootpacks and partial descents (i.e., as opposed to the typical venue's shortened course option of skipping a final lap or two), participants of different speeds are often mixing it up along the way.
Read the detailed description and you do the math!
(Might be 25...)
Overall, if you're looking for a first-ever rando race, the Berkshire East shortened-course option (i.e., just skinning & skiing, five laps or even less) is probably your best introduction to the sport.
(And if you're a seasoned vet, then dial in those transitions beforehand!)
"The Magic" @ Magic Mountain
Fast efficient skinning, a very steep bootback (only for the full competitive course), and skiing that is either difficult (if Black Line is our best option) or even far more difficult (if Red Line is open).
Overall, if you want straightforward efficient ascents combined with tough descents, then this is your race venue!
"The 'Bolt" @ Mount Greylock
The Northeast's first (in 2014) and still the only 100% backcountry rando race!
With backcountry conditions for both the up & down (as well as for waiting around at the start & finish), this is a race only for skiers with prior backcountry experience.
In 2015, the full competitive course entailed two laps from the base at Greylock Glen to the summit.
Starting in 2018, the full course entails three shorter laps but on only the core of the Thunderbolt ski trail, yet with a bootpack (and additional partial descent) on the most challenging descent segment, "The Big Bend"!
Even with the (relatively) shorter laps, the descents are still long, with variable backcountry conditions, and without any groomed terrain for a rest.
Overall, although this course has only a relatively modest ~5,000' vertical, the challenge is far from modest -- but the reward is worth it!
[On hold after its 2017 debut, but archived here for a possible future return.]
The smallest mountain in the series but the most accessible to the most number of skiers.
Fast efficient skiing followed by a challenging partial descent, leading into a skin>boot>skin partial ascent, then a full descent.
Repeat, then repeat again!
"The Sun" @ Bromley Mountain
[For 2018, bootpack will be added]
Fast efficient skinning.
Lots of moguls (rerouting starting in 2015 to eliminate almost all the groomers), but only lower-expert pitch, and southern exposure in mid-March.
A short easy bootpack (new for 2018).
Overall, well, it's fun!
"Something Bigger @ Sunday River
The best overall course layout in Eastern North America.
Nothing else even comes close.
[Period -- or should that be an exclamation mark?]
Sunday River's unique layout of a series of adjacent peaks combined with a segregation between the upper and lower peaks allows for an out-and-back tour while not repeating, overlapping, and/or intersecting any of the "out" vs. "back" segments.
The skinning is efficient and the skiing is challenging.
Plus a bootpack too.
Be there or miss out in a big way!