  We identify a set of planetary systems observed by Kepler that merit transit
timing variation (TTV) analysis given the orbital periods of transiting
planets, the uncertainties for their transit times and the number of transits
observed during the Kepler mission. We confirm the planetary nature of 4 KOIs
within multicandidate systems. We forward model each of the planetary systems
identified to determine which systems are likely to yield mass constraints that
may be significantly improved upon with follow-up transit observations. We find
projected TTVs diverge by more than 90 minutes after 6000 days in 27 systems,
including 22 planets with orbital periods exceeding 25 days. Such targets would
benefit the most from additional transit timing data. TTV follow-up could push
exoplanet characterization to lower masses, at greater orbital periods and at
cooler equilibrium temperatures than is currently possible from the Kepler
dataset alone. Combining TTVs and recently revised stellar parameters, we
characterize an ensemble of homogeneously selected planets and identify planets
in the Kepler field with large enough estimated transmission annuli for
atmospheric characterization with JWST.
