Hi there Danby fellow, I grew up in the Dryden area and now live near Hershey.
You won't find the "EcoVillage at Ithaca" crowd between Harrisburg and Reading. This area is much more politically conservative, what passes for "liberal" here would be center-right-wing to the average Tompkins County
non-14850 resident, and wouldn't even register on the scale of center Ithaca politics.
You will find many small towns with a higher density residential housing stock. Typically, the older communities in this corner of PA have attached or semi-detached houses in the urban core. It's much higher density than even older neighborhoods of Ithaca or Binghamton. Unfortunately, especially for this level of density, public transit is pretty much non-existent - there are some buses but nothing that registers to a TCAT standard. The US 422 corridor is a commuter's nightmare - think average 15 mph or less. Hershey to Reading is over an hour either on I-81 or I-76 (and getting to and from those) - maybe 1.5 hours on weekdays if you follow the seemingly direct US 422. Think of 30+ miles of the couple blocks of South Meadow Street by the Ithaca Wegmans and you get the idea.
You may also face sticker shock for property values coming from Central NY if you don't realize that CNY has some of the lowest home values in the country. The Lebanon Valley is much more affordable than areas in PA to the south and east or the I-95 corridor but it's still several ouch clicks over CNY.
Once you get past all that there are a number of communities of possible interest.
Hershey - supposedly has the best public schools in PA outside of very high rent Philly and Pgh suburbs. Home to the Penn State medical school. Here you have money to go with the prevailing conservatism. Recently got rush-hour public buses to Harrisburg. See above for the drive to Reading. Three factories remain as sources of chocolate and peanut butter smells in the air but the workers mostly live further east due to being priced out. The in-town housing is mostly detached with a few semi-detached, less culture shock coming from a CNY basis. It is also expensive, maybe 3x what you'd pay in Ithaca. Property taxes are maybe 1/3 x on a CNY basis, which is considered high by PA standards. Outside this core there are McTownhomes and McMansions. One saving grace is that some of the newer Derry Township (Hershey doesn't exist as a political entity) are connected by a bike trail to the medical complex, not really to the old core.
Hummelstown - The Borough of Hummelstown contains the locally owned shops Hershey doesn't. Much older housing stock higher density community. Taxes as high as in Hershey for less services and not quite as high ranking schools, but the taxes will seem silly low coming from NY state. Newt Gingrich grew up here. The Hummelstown mailing address carries far out of the old town into both Derry Twp (see Hershey, above) and non-Derry Twp McSuburbs.
Annville - Small town home to small private Lebanon Valley College. Rehabbed theater and coffee shop. Growing pride in community business district and housing stock. Reasonable escape to I-81 for commuting.
Mount Gretna - tiny town, home to the Pennsylvania Chautauqua, arts festival, playhouse, tiny older homes under trees, some not yet converted from seasonal summer places. On bike trail and nearly surrounded by publicly-owned woods. Much more of a summer "scene" than winter. Gotta drive a ways to work.
Cornwall - Newer and older homes mixed in the hills east of Mount Gretna which is a short drive or bike ride away. Even the newer homes seem not quite so McSuburban as other nearby locales.
Lititz - If what you're looking for is intercommutable from Harrisburg to Reading, vs. on the map between, this might be worth looking into. Founded by a religious community, the town has many locally owned shops including its own chocolate and pretzel companies, including local artist shops and the like. Newer homes on outskirts again not quite so McSuburban as nearby communities.
Lancaster - Pronounced "LANK-uh-stir." Take the train to Harrisburg or Philadelphia, drive a newer expressway to Reading. Has both urban problems and urban renaissance. Home to Franklin & Marshall college and the Millersville state university nearby. Others here will know more about Lancaster.
Elizabethtown - Smaller than Lancaster, closer to Harrisburg. Train to Hbg or Philly, longer drive to Reading. Hosts private college larger than some of the others. Mix of older and McSuburban housing.
Lebanon - Older housing stock, growing working-class Hispanic community transitioning from Pennsylvania German.
There seems to be a bit of hippie-ish sensibility in the countryside east of Hamburg. Just west of Hamburg is a Cabela's superstore and attendant sprawl. Just northwest of Hamburg is tiny Port Clinton, on the Appalachian Trail, row homes with no sewage treatment bisected by a busy highway.
If you're looking for a place away from others in the woods like many have in Danby, the belt of territory just north of I-81 and I-78 might offer possibilities. However, the sounds of artillery from Fort Indiantown Gap carry far (noticeable even in Hershey some weekends), and the chicken plant smells from Fredericksburg carry a little ways out too. Much of this territory will have Grantville or Jonestown postal addresses for searching the realtor websites. (Watch the purple Kool-Aid jokes.)