If it has the 5.7/hemi you need to be aware of the hydro lock issue lot of threads on this you can search for. Likely already occurred on this one since you said new engine, but it can happen again if you do not take steps to prevent it. Fuel pumps are a common issue where they do not fail, but crack around the plastic where they mount to tank cause a constant engine light for small/large evap leak. Rust of rear fenders especially drivers side. Rear hatch by handle also a common rust spot. For the 5.7 recommended spark plug interval is 30k miles which is something to be aware.
I just hit 200k miles on my 04 and have owned it since 160k when I bought it with a bad engine for $800 little over 5 years ago. Engine rebuild, fuel pump, O2 sensor, and currently a break in exhaust pipe I have not fixed yet in 40k miles I have owned it, but engine rebuild I bought knowing was needed. Also, things more general maintenance like shocks, brakes all around, plugs (twice, rebuild and 30k miles later), replaced rusty hatch with a good junk yard find, new tensioner, idler pulleys, and belt.
Most issues I have had all relate to engine rebuild. Oil pan gasket did not seal right so have been leaking oil since rebuild, but have to nearly pull the engine to pull oil pan on the 4wd version so living with adding oil every 700-1000 miles, and electric ground connection is not as strong since rebuild as I likely missed a few points at back of engine that should of had ground strap attached so ran my own 8 gauge wire to key spots as new grounds, but those connections have to be cleaned up every couple years when truck starts to be slow to turnover. Overall, I consider it a reliable vehicle. Use it as a secondary vehicle to keep miles off our newer vehicles.
