  This paper studies the dynamical evolution of young stellar clusters with $N$
= 100 - 1000 members. We use N-body simulations to explore how evolution
depends on system size $N$ and the initial conditions. Motivated by recent
observations of extremely young systems, this study compares subvirial and
virial starting states. Multiple realizations of equivalent cases (100
simulations per case) are used to build up a robust statistical description of
these systems, e.g., distributions of closest approaches, mass profiles, and
distributions of radial locations. These results provide a framework from which
to assess the effects of these clusters on star and planet formation. The
distributions of radial positions are used in conjunction with distributions of
FUV luminosities (also calculated here) to determine the radiation exposure of
circumstellar disks. The distributions of closest approaches are used in
conjunction with scattering cross sections (calculated here from $10^5$
scattering experiments) to determine the probability of solar system
disruption. We also use the nearby cluster NGC 1333 as a test case. Our main
conclusion is that clusters in this size range have only a modest effect on
forming planetary systems: Interaction rates are low so that the typical solar
system experiences a single encounter within 1000 AU. Radiation exposure is
low, with median FUV flux $G_0$ = 900, so that photoevaporation of disks is
only important beyond 30 AU. Given the low interaction rates and modest
radiation levels, we suggest that solar system disruption is a rare event in
these clusters.
