Dwarf galaxies are excellent test particles for studying dynamical properties of the Local Group (LG) and the role of environment in quenching of star formation in low-mass galaxies. In this context, galaxies at the edge of the LG are of particular interest. They enable an estimate of the mass of the LG throught the radius of the turn-around surface. However, how dwarfs can be located at such large distances from the barycenter of the LG is still an open question. It may be that these galaxies are on their first infall into the LG potential well. Alternatively, they may have been close to their first orbital apocenter when the LG decoupled from the Hubble flow, the so-called splashback radius. Depending on this issue, the enviroment the dwarfs have moved through can be quite different. This environment also affects their star formation history through e.g. quenching. Here we propose to measure proper motions (PM) 4 dwarfs located at the edge of the LG: 2 dwarf irregulars (LeoA and Sag dIrr) and 2 dwarf spheroidals (Cetus and Tucana). These are the only dwarfs at the edge of the Local Group with first epoch archival data for PM measurements and star formation history determination. We will construct full three-dimensional velocity vectors, trace back their orbits, calculate the LG Mass, and determine whether past interactions with the MW or M31 can explain their different morphologies and star-formation histories.