The modification is tricky and extensive but if you know what you're doing, here's my setup. On the freelander side there's not much meddling since you want to retain everything as stock.
Mechanically, the tricky part is getting the engine and gearbox to be perfectly centered since the two will obviously not match, when doing the adapter plate take that into consideration. The flywheel from the k-series engine had the holes filled in then drilled to match the toyota crank. That way the original clutch setup and starter on the gearbox side were retained.
The intake assembly with the throttle position sensor and butterfly from the K-series were used. The Idle Air Control Valve was fitted between the intake and butterfly assembly. A hole was drilled on the intake for the MAP sensor.
On the toyota engine the sensors from the k-series engine were fitted/ replaced the toyota sensors, namely - Oil pressure, Oil temperature, Engine coolant temperature, Camshaft position sensor (CMP), Crankshaft position sensor (CKP).
Since the toyota engine does not have a CMP sensor, a half-cylindrical shape reluctor was added to the exhaust camshaft and a hole was drilled on the right side of the cylinder head to pick the signal. Finally, the CKP sensor was installed on the rear side on the block on the flywheel side to pick the signal from the flywheel for ignition timing.
With the hard part over, the k-series fuel injectors were machined to fit into the toyota fuel rail and the toyota ignition coils were also replaced. With this setup the ECM reads the the sensors and controls the engine exactly the same way it would with the original 1.8l k-series engine.