Hi Kadin,
Lares Trek
You do not need to hire a travel agency or book something in advance to hike the Lares Trek. You can
read a detailed itinerary of the Lares trek here.
Machu Picchu
Try to go as early as possible. The train will stop in Aguas Calientes. From there you can either hike up the hill or take a bus to Machu Picchu. Tickets to enter Machu Picchu can no longer be bought at the entrance to Machu Picchu itself. You now have to buy the entrance tickets at the Machu Picchu Cultural Centre in Aguas Calientes (10m from the main Plaza, opens at 5:15am) or in Cusco at the Instituto Nacional de Cultura (INC) offices which can be found at Calle San Bernado a few blocks from the main Plaza de Armas). You can find excellent information about getting to Machu Picchu here.
Best wishes,
Mark