Another program you might want to look at and is fairly user friendly and will read all the shape file and image extensions as the ESRI (Arc View) products will, is Accuglobe, you can go to their website http://www.accuglobe.net/ and it is a free download. Also remember there is a lot of data out there from state and county offices, check their websites for GIS data, you are bound to find them. As for GPS mapping, if you have the capabilities, you can download a trial version of Arcpad and intall that onto a pda with a gps that operates windows mobile, it gives you the full program for a limited time. Have fun!
Try to research post processing capabilities for your GPS also. This will greatly enhance your horizontal accuracy.
As mentioned ArcGIS with a sub-meter GPS would be ideal, but a Garmin csx60 handheld GPS unit and Google Earth would do the trick. You can simply upload the data to GE. One thing to remember is that a dot on a map will likely cover several meters, so sub-meter is not that critical if all you want is a map. It's another story if you want to use the GPS to get back to a particular tree. The accuracy of that little Garmin is quite impressive though, even in forest conditions. With a $20 add-on you can even load aerials on to the unit.
Another concept if you want true XYZ location with 6" horizontal accuracy and sub-6" vertical accuracy (engineering quality) is aerial mapping. I work for a company that does that so that's my bias. We provide the raw base data by collecting planimetric and terrain (contour) data using photogrammety from aerial stereo imagery. What that means is we'd be able to fly over the trees and use the imagery in a digital stereo software environment to collect a data point at the base of the tree where it sits on the ground. That point would have its own unique ID number and XYZ location. We'd also use the imagery to collect a point field of your whole woods and determine the high's and lo's so you knew which way your sap would flow from any location. Therefore you could locate where to run your mainline exactly by using our raw base data in the GIS package of your choice. As well we could provide orthophotos and overlay that with the vector map data. Print it off or do what you'd like. Technically this is your most accurate means of data collection outside of hiring a surveyor to survey every tree in your woods. Today's gps is getting better but still not as good as aerial photogrammetry. The obvious problem is that aerial mapping isn't cheap, but it's certainly effective especially if your woods doesn't have alot of slope and every percent of grade counts. Here's the shameless plug (link to our company's website.) www.continentalmapping.com
2011 and prior
40+ gravity
transport to a friends evap
borrowed 4 wheeler as a mule
2012
40 Gravity (buckets and main line tubing)
Boil over open oan
Borrowed 4-wheeler as a mule
2013
50+ taps
2X3 Evap from A&A Metal Shop
Barn built from pallets
borrowed 4-wheeler.