1
There are numerous shuttles daily from Nairobi to Arusha. These shuttles originate in central Nairobi, then pass by Kenyatta Airport where you could arrange to be picked up. The problem is, the last shuttles of the day leave around the same time you will be landing.Try going to http://www.riverside-shuttle.com and contacting them to see if they can suggest anything.
If you get yourself into central Nairobi, you can catch an ordinary bus or matatu to Namanga (the border town) or right through to Arusha, but again, you may be too late in the day. Buses are not supposed to operate in Tanzania after dark.
Look into the possibility of getting a connecting flight to Kilimanjaro International Airport (which is near Arusha) or to another airport where your safari company can meet you.
3
For Shuttles to Arusha or Flights over this period, reserve in advance with a reputable agent to avoid last minute disappointment as over this period, Most people are traveling from Kenya to Arusha for their Holidays.Safari Africa Guide
4
Am not sure of the delays of the International or local flights that you will arrive byBut if the arrival can be exactly 1345 you can make it to arusha the same day, just book the following shuttles
Jamii Impala Shuttle and Riverside , They all ave the same schedule

