A whole bunch of quests in the Farmlands are connected to the Plague Quest, centered on Dr. Elrath: the harvest disaster, fitting/stolen keys, curing the ill in the quarantine section etc. Therefore it is best, not to encounter Dr. Elrath too early in the game, because you meet him only twice. We start with the quarantine section: As soon as you are near the main gate, a cutscene occurs and you see Elrath talking with the guards and vanishing - let him go. If you try to enter this section, the guard will tell you there is no access due to infection danger. You can enter this area, but use the west side entrance, a house with a hooded stake in front of it. You can use lockpick level 1 or talk to Lain.